Preface

First published 20 years ago, this book filled a gap in the literature being the first reference manual to include the then rapidly growing trussed rafter methods of roof construction. The second edition was expanded to include attic roofs and loft conversion, followed by the third edition which updated all text and drawings to the current standards of 1999.

This fourth edition details the rapid growth in engineered timber components and in particular their use in room-in-the-roof construction, dealing both with the floor and the rafter diaphragms. These components and construction methods have been dealt with by an additional chapter dealing with I beams, prefabricated roof panels and roof cassettes. The constructions are explained with the aid of numerous drawings.

Like many other building topics the roof is one of the those subjects with which everyone is familiar until it comes to actually detailing or cutting the timber components concerned, and then the lack of knowledge becomes apparent. Furthermore, research soon confirmed the total lack of in-depth text on the construction of trussed rafter roofs, a method of construction now used on over 90% of house construction in the United Kingdom.

The book aims to describe with the aid of many drawings, not the structural design analysis of the roof structure, but the design of the roof assembly as a whole entity rather than individual elements in isolation. Recognising the growing trend to refurbish older homes, the traditional or 'cut' roof is described. The bolted and connec-tored roof is dealt with in some detail, for despite the popularity of the trussed rafter this older system is still chosen by some builders. The bolt and connector truss roof is particularly popular for small extension projects where it often continues the construction of the original roof.

Chapters 6 and 7 cover the trussed rafter roof in great detail, dealing with the often misunderstood hip construction, valleys, girder truss assemblies, and the forming of openings in roofs as well as attic constructions. Chapter 7 compares the various truss plate systems and has been made as accurate as possible, bearing in mind the many changes being introduced by these manufacturers to their engineering services and computer programs and with the constant updating of BS 5268: Parts 2 and 3 and Eurocodes.

Chapters 9 to 12 deal with all aspects of loft conversion to attic rooms of the roof structure itself. The text does not address the subject of fire protection and escape, or the installation and alteration to services. Variations between buildings being converted in shape of roof, size, number of storeys, and intended use of attic are so great that it is impossible to cover all situations likely to be encountered. My text and illustrations will, however, cover most common constructions.

It is the intention that the book be used for reference, and to this end there is a small degree of repetition between chapters, and there is frequent cross-referencing between chapters for both text and illustrations. Although some basic common knowledge of building is anticipated, most terms used are fully described, making the book equally suitable for use by both the building student and the professional. The text takes into account the latest issues of both the British Standard for timber engineering, BS 5268: Parts 2 and 3, and the Building Regulations 2000 and all subsequent amendments. However, as it was felt to be outside the scope of this book, the subject of fire resistance and spread of flame has not been dealt with. Reference should be made to Building Regulation Approved Documents.

For ease of reference all drawings have been given a number, the first digit of which refers to the chapter, and the second and third digits being the numerical sequence in that chapter. Generally, shading has been used to highlight those elements discussed in the text to which the illustration applies. Most drawings have been produced in perspective form to aid quick appreciation of the three-dimensional nature of all roof structures. Chapter 2 sets out the terms used throughout the book to describe roof and truss shapes, and individual roof members. The specialised terminology of the trussed rafter is given in Fig. 6.2. Finally for those involved in the design aspects of roof structures, the British Standard 5268: Parts 2 and 3 should be available for ready reference.

C.N. Mindham 14 Harrowden Lane Finedon Northants NN9 5NW

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