ihs brepress logo bre connect Website

Order BRE books from IHS BRE Press

t: +44 (0) 1344 328038
f: +44 (0) 1344 328005
e: brepress@ihs.com

Online:
www.ihsbrepress.com

 

 

CIS Service Website

Call +44 (0)1344 328300 to discuss your online construction information requirements

Home > Building elements and structures > Roofs and roofing

Roofs and roofing


A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building ¿ a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32 

A quality system for achieving Zero-Leak roofs using profiled metal
'Zero Leak Roofs' (ZeLro) aim to ensure best practice in design and construction of profiled metal roofs, so (as the name implies) they do not leak. This book is a quality system for achieving Zero Leak Roofs using profiled metal. It focuses on client expectations, implementation and weaknesses in current design and construction. This guidance is applicable to constructing watertight, cost-effective roofs, free from defects, that will avoid later maintenance costs. Other features include installer selection, supplier roles, responsibilities and safety. EP54 

American plywood in roof construction
Plywood has characteristics that make it ideal in today's construction market where performance, process and price are main drivers. This guide will help users of American plywood to derive the maximum benefits from plywood in roof constructions in terms of performance, durability and cost-effectiveness. It will enable users to make the right decisions when specifying, selecting, designing and fabricating roof constructions using plywood. It has been written by BRE in partnership with APA (the Engineered Wood Association). BR369 

Bituminous roofing membranes: Performance in use
This paper discusses a laboratory test measuring the cold bending temperature of a wide range of bituminous roofing sheets, and the implications for current site practice. IP7/95 

Bracing trussed rafter roofs
Shows how timber bracing may be installed in typical trussed rafter roofs of up to 12 m span, advises on materials and where and how to fix the bracing normally needed for dual-pitched and mono-pitched roofs. GG8 

Building a new felted flat roof
With advances in materials and design, weathertightness and energy performance of modern flat roofs has improved. This Good Building Guide focuses on one of the commonest examples of a new flat roofed building – a house extension. Here a flat roof may be the only practical option, and also the cheapest. This Guide advises on how to make a good job of a new felted roof extension. GG36 

Considerations in the design of timber flat roofs
Draws attention to some of the problems which can arise with timber-based roofs and gives guidance on how these problems might be prevented in future. IP19/82 

Designing roofs for climate change: Modifications to good practice guidance
The climate change models produced by the UK Climate Impacts Programme (UKCIP) in 2002 gave an insight into predicted weather changes, with higher summer temperatures and milder winters, but more rainfall. Roofs being designed now will have to cope with these changes and designers need to take this into account in their designs. This Digest gives recommendations on proposed modifications to guidance on good practice in roof design and construction for many types of roof in the light of predicted climate changes. It is based on the views of roofing industry experts as part of a Partners in Innovation project led by BRE. DG499 

Designing roofs with safety in mind
This Paper reports the findings of a committee of roofing experts who examined HSE data on accidents with a view to establishing the design decision which led to the underlying cause of the accident. It is aimed primarily at architects and designers of roofs but is also relevant to material suppliers and installers and others working on roof construction. IP7/04 

Erecting, fixing and strapping trussed rafter roofs
Guide for site supervisors and building inspectors, showing normal arrangements for fixing and strapping domestic roofs up to 12 m span, to provide a sound platform for roof coverings and contribute to the stability of the roof and gable ends. To be used with GG 8. GG16 

Flat roof design: bituminous roofing membranes
This Digest will help designers, specifiers and flat roofing contractors to specify durable bituminous sheets. This is one of a series of Digests giving guidance on design and specification of flat roofs. Other Digests in the series are: 312 The technical options; 324 Thermal insulation; 372 Waterproof membranes. DG419 

Flat roof design: the technical options
Summarises the requirements which must be considered when designing a flat roof and outlines the technical options available to designers, describing the advantages and disadvantages of each, and the costs and other considerations. DG312 

Flat roof design: thermal insulation
The need to conserve energy in buildings has led to improved standards of insulation, including those of flat roofs in domestic, public and industrial buildings. This Digest describes the properties required of thermal insulation in flat and low-pitched roofs, reviews the wide range of products available and suggests criteria for selection. DG324 

Flat roofs: assessing and making roof repairs
Most flat roof coverings need repair or replacement during the life of the building. This can be anything from a small patch repair to renewal of the roof covering or even rebuilding the whole roof structure. Part 1 of this Guide gives advice on how to carry out a detailed assessment of a roof in need of repair or refurbishment. Part 2 gives guidance on how to plan and carry out remedial work. GR16 

Green roofs and façades
Green roofs and façades on buildings offer a wide range of benefits, including attenuation of rainwater run-off, improved thermal stability and energy conservation, enhanced air quality, wildlife habitat and open space. This book provides an accessible overview of the development of green roofs and the contribution they can make to sustainable development. It explains the benefits of their use, and identifies the key aspects that must be considered in designing, building and maintaining them. It is fully illustrated with numerous examples of successful applications from around the world. Features / Benefits Green roofs are part of the wider green and sustainable development agenda Provides accessible guide to green roofs Meets the rapidly growing interest in green roofs Numerous illustrations of green roofs and facades from around the world. Readership Architects, landscape architects, planners, designers, building services engineers and students of these disciplines. Building owners and developers, construction contractors and materials suppliers EP74 

Handbook of imposed roof loads
BS 6399: Part 3 includes more comprehensive information on imposed roof loads than previously given in BS 6399: Part 1:1984 or in CP 3: Chapter V: Part 1: 1967. This handbook assists with its interpretation and application. BR247 

Inspection and maintenance of flat and low-pitched timber roofs
Discusses the need for regular inspection of flat and low-pitched roofs which incorporate built-up beams or other composite timber structures. IP15/82 

Insulated profiled metal roofs
This Good Building Guide highlights typical profiled metal roof constructions, some of the technical risks associated with increased levels of insulation (such as potential risk of condensation) and the design aspects which should be considered.  GG43 

Insulating roofs at rafter level: sarking insulation
This Guide highlights sarking insulation, a system of roof insulation where the insulation material is laid between and over inclined rafters. It can satisfy the thermal requirements of building regulations and allow complex roofs to be more effectively insulated with a reduced risk of thermal bridging and condensation problems as the roofing timbers are kept at or near internal environmental conditions. This Guide provides advice on specifying sarking insulation and on avoiding the associated technical risks. GG37 

Load sharing between rafters in traditional timber roof structure
Reports on the development of a theoretical model which may be used to estimate the amount of load sharing provided by tiling battens spanning between rafters in a traditional timber roof structure. IP5/82 

Loft conversion
Applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. Part 1 provides information on the suitability of different types of lofts for conversion and the structural considerations. 8 pages. Part 2 considers safety requirements, thermal and sound insulation, and installation of services. 6 pages. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small- and medium-sized building companies, architects, surveyors and home owners. GG69 

Loft conversion
The first part of this Good Building Guide provides information on the suitability of different types of lofts for conversion and the structural considerations. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part considers other safety requirements, insulation and installation of services. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/1 

Loft conversion
The second part of this Good Building Guide considers safety Requirements, insulation and installation of services. It applies to loft conversions in houses not more than two storeys high, with no more than two habitable rooms and a maximum floor area of 50 square metres, and only to dwellings in single occupancy. The second part provides information on the suitability of different types of lofts for conversion and the structural considerations. Features / Benefits Gives concise introduction to the principles and practicalities of loft conversion. Provides clear technical advice and solutions. Draws on BRE experience and research, and other reliable sources. Readership Small and medium-sized building companies, architects, surveyors and home owners. GG69/2 

Maintenance costs of flat roofs
Although flat roofs have a reputation for being expensive to maintain, there has been a shortage of quantitative information on the subject; research to date has concentrated on technical investigation of failures. This paper summarises two maintenance studies that use a statistical approach. IP11/81 

Mastic asphalt for flat roofs: testing for quality assurance
Severe winter conditions have seen the failure of standard types of mastic asphalt laid over thermal insulation. BRE tests show that the performance of mastic asphalt can be significantly improved by the addition of appropriate polymers. One of these tests may also have potential as a quality control test for mastic asphalts used in flat roofing. IP8/91 

Moisture in a timber-based flat roof of cold deck construction
Deals with moisture which penetrates the roof from inside the building in the form of vapour. IP35/79 

Re-covering old timber roofs
How to assess the condition of old timbers in roofs that might be subjected to higher loads from new tiles or slates. DG351 

Re-covering pitched roofs
Highlights key points to watch out for when renewing a roof covering, which would not normally arise in new work. GR14 

Roof loads due to local drifting of snow
Following a review of some areas of difficulty, BS 6399-3 was amended in 1997. The main changes related to determining load shape coefficients for local drifting of snow, and using the snow load statistical factor to produce estimates of loads with probabilities of exceedance different from 0.02. This Digest presents background information and design requirements for local snow drift loads on roofs in line with the amended British Standard. It is aimed at architects, structural engineers, contractors, and manufacturers and suppliers of roofing systems.  DG439 

Roofs and roofing
A key reference source on all aspects of roofing. Assists in the identification of defects and their causes, establishes how to correct them and how to avoid them in the first place by careful design and maintenance. It explains the basic functions of all roofs, then discusses short span domestic pitched and flat roofs, medium span commercial, public and industrial roofs, and long span roofs. It has over 200 photographs and 100 drawings of roofs and construction details. Currently supplied as a black and white digital reprint. A new edition will be published in June of 2007.  BR302 

Roofs and roofing pack
A valuable reference library of BRE Digests, Good Building Guides, Good Repair Guides and Information papers on roofs and roofing. One of a series of 19 compilations of BRE expert guidance and advice and presented in an attractive ring binder for ease of use. Exceptional value. Features / Benefits Exceptional value 29 BRE publications compiled into a single binder Forms an easy to use library of key information and guidance Readership Construction professionals  AP263 

Safety considerations in designing roofs
This Digest reports the findings of the Designing Roofs with Safety in Mind Partners in Innovation project sponsored by the Department of Trade and Industry. It is intended to give guidance to enable effective implementation of the Construction Design and Management (CDM) regulations and result in the construction of safer roofs. DG493 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually, prefabricated or site-made trusses to support in situ fitted purlins and rafters, or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commonest form of construction but there are situations where a purpose designed and site-built roof may be preferred. Part 1 explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several different ways. They can be built in situ with each piece cut and fitted individually, they can use prefabricated or site-made trusses to support in situ fitted purlins and rafters, or they can be built with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the most common form of construction in recent years but there are situations where a purpose designed and site-built roof (often referred to as a cut roof) may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/1 

Site-cut pitched timber roofs
Pitched roofs can be constructed in several ways: in situ with each piece cut and fitted individually; with prefabricated or site-made trusses supporting in situ fitted purlins and rafters; or with prefabricated trussed rafters forming the complete roof structure. Prefabricated roofs have become the commones form in recent years but there are situations where a purpose designed and site-built roof may be preferred. Part 1 of this guide explains the principles of this type of construction and describes patterns of roof structure and design considerations. Part 2 describes a method of fabricating and constructing a typical domestic site-built roof. GG52/2 

Slate and tile roofs: avoiding damage from aircraft wake vortices
The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest helps building owners, occupiers, roofing specifiers, contractors, installers, and local and airport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. DG467 

Stability under wind load of loose-laid external roof insulation boards
Gives guidance on the uplift pressures to which loose-laid roof insulation boards can be subjected, and how they can be restrained using ballast or mechanical fixing. DG295 

Structural appraisal of buildings with long-span roofs
Explains why periodical structural appraisal of buildings with long-span roofs is especially important. It also indicates the commonly occurring defects and gives guidance on appraisal of structure and components. DG282 

Survey of performance of organic-coated roof sheeting
Results of a survey of building and chartered surveyors specialising in commercial and industrial buildings and of industrial building owners to assess the performance of profiled metal roofing sheet in the UK. Organic-coated zinc galvanised sheet was the most common roofing material identified and PVC the most common organic coating. BR259 

Swimming pool roofs: minimising the risk of condensation using warm-deck roofing
Successful roof design demands much more rigorous consideration of condensation risks than is needed for roofs of other buildings. This Digest outlines the steps in designing a warm-deck roof in which the condensation risk is minimised. It can also be used to solve problems in roofs of existing pools. DG336 

The movement of foam plastics insulants in warm deck flat roofs
In recent years a high incidence of premature failure has occurred with warm deck flat roofs. This paper describes research which has been carried out by BRE to investigate this problem and gives design recommendations based on the findings. IP6/84 

Thermal performance of lightweight inverted warm-deck flat roofs
BRE research shows that an inverted warm-deck roof combined with a lightweight deck can, during rainfall, lead to reduced thermal performance and the risk of condensation in the roof. The paper explains that a simple design modification could reduce this risk. IP2/89 

Tiling and slating pitched roofs
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64 

Tiling and slating pitched roofs: Design criteria, underlays and battens
This three part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 1 covers general principles applicable to all forms of tiling and slating, together with criteria where requirements for ancillary materials and practices are common to both tiles and slates, such as weather resistance and underlay specifications and some aspects of work on site. Parts 2 and 3 describe battening, nailing and product and material quality requirements for tiles and slates. GG64/1 

Tiling and slating pitched roofs: natural and manmade slates
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 3 covers battening, nailing and product and material quality requirements for slates. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Tiling using plain and profiled clay and concrete tiles is described in Part 2. GG64/3 

Tiling and slating pitched roofs: plain and profiled clay and concrete tiles
This 3-part Good Building Guide deals with the upper surfaces of pitched tiled or slated roofing. It concentrates on those aspects of tiling and slating that have been most frequently observed in BRE site investigations of roofing schemes, which could lead to deficiencies in the performance of the completed roof. The objective is to provide practitioners with a summary of the main good practice criteria. Part 2 covers battening, nailing and product and material quality requirements for tiles. Advice on weather resistance, underlays and thermal insulation for warm roofs is contained in Part 1. Slating using natural and manmade slates is described in Part 3. GG64/2 

Timber stress grades for trussed rafters
Discusses timber stress grades and concludes that to obtain the same permissable spans as for the composite grade, timber of ss grade should be used and the resulting yields of this grade from commercial parcels should not be significantly lower than those of composite grade. IP15/80 

Trussed rafter roofs
This paper summarises of the results of surveys of the manufacture, site use, and performance in service of trussed rafters, and the significance of copper-chrome-arsenic treatment on the incidence of corrosion of galvanised metal plate fasteners used in trussed rafters. It also gives conclusions and recommendations based on these results. IP14/83 

Trussed rafter roofs - load distributions and lateral stability
Summarises the load sharing capabilities of the components of a laboratory test roof constructed with fink trussed rafters. The lateral stability of the roof with different diagonal bracing systems in the plane of the rafters was assessed. IP14/82 

Ventilated and unventilated cold pitched roofs
In a 'cold' pitched roof, the insulation is fitted at ceiling level, but there is a risk of condensation on the underside of the roof. Since the 1960s, the accepted solution has been to ventilate the loft space by openings to the outside at eaves and ridge. More recently, vapour permeable underlays are sometimes used as an alternative. With the introduction of the unventilated cold pitched roof, the general principles and risks need to be clarified and approved construction techniques identified. By giving guidance on the technical risks associated with ventilated and unventilated forms of cold pitched roofs, this Good Building Guide responds to some of the confusion and conflicting views. GG51 

Ventilating cold deck flat roofs
Suggests that there is need for increasing ventilation where natural draught ventilation is low or where roofs are complex. Offers guidance for designers and maintenance managers IP13/87 

Ventilating thatched roofs
Thatch is permeable to air and moisture; when constructed traditionally it is a weather resistant, breathable and highly durable roofing material. However, the introduction of impermeable plastics, the requirements of building regulations for additional insulation and reduced air leakage, can increase the risk of condensation within the thatch, so affecting its durability. This Guide explains how to reduce that risk by introducing cavities and ventilation below the thatch. It applies to new roofs and where the thatch of an existing roof is to be replaced. Local authorities may require a consent application for the removal of thatch or if the insertion of new materials would change the behaviour of the roof. GG32