Much of the work of architectural practices, particularly small ones, involves repair and maintenance to existing buildings, whether as specific projects or as part of a larger project. There is much sound advice available on repair especially from the bre.
The book Structural Repair of Traditional Buildings adds to this useful information. However, the author, an experienced civil and structural engineer, is concerned about the tendency of designers to treat old buildings in the same way as if they were designing new ones. So this book highlights the differences in approach between new design and building repair. The author notes that when repairing old buildings designers often exercise the same caution as they would when designing new buildings. He argues that in an old building, that has been around for many years the existing structure is generally sound and often would not need to be brought up to modern standards. For example he writes 'in the course of minor repairs the foundations are brought up to 'modern standards' at great expense, when the money could have been spent on something more useful.' This, he suggests, is partly a lack of confidence. 'Designers have the confidence to apply only the principles they have learned for new design.' To a large extent it is because of inexperience as well as legitimate concern over professional liability - many would argue that a structure standing for a long time does not guarantee that it will continue to do so.
The aim of this book is to address the principles appropriate for the repair of old buildings and particularly those relevant for identifying the causes of problems.
Although the subject is structural repair it is not just for structural engineers. The book is aimed at all those with an interest, as well as students. It is divided into four parts and also has various appendices. Part one tackles the basic principles of structural behaviour, soil behaviour, uncertainty and performance, conservation and diagnosis. Part two looks at defects and the causes of structural damage and deterioration. Part three considers the options and discusses the purpose of the repair. Part four considers the management issues, from preventive maintenance to planning and conducting the work.
A recurring theme is the use of modelling to understand how an existing structure works. Many of those who have taken apart old buildings will recognise that some apparently defy structural logic. Careful modelling enables a deeper understanding of this and is a useful informative tool. The chapter on 'Uncertainty and Performance' compares how uncertainty is managed in the design of new buildings to how it is managed in the repair of old buildings. One of the key differences is that a new building's structure is designed against characteristics afforded to the materials and particular design, whereas in an existing building you can see what is actually happening.
While many experienced architects will be familiar with the issues that the book raises, it is a useful starting point for those less familiar with repair to old buildings. However, it will not replace professional advice on anything but the simplest problem.
Structural Repair of Traditional Buildings, Patrick Robson, Donhead, 320pp, £37