The purpose of this book is to assist architects, surveyors and engineers to recognise, diagnose and avoid problems in buildings, and to decide to obtain specialist assistance if appropriate. Where a problem leads to litigation or arbitration a much more critical assessment is required, usually resulting in comments on the problems in relation to the contract documents and normal good practice, as represented by British Standard specifications and codes of practice and other readily available sources of guidance. Where an action is against an architect, surveyor or engineer, an expert in the same discipline will be required to give an opinion on professional duties and the actions that a reasonably competent and diligent person should have taken in the circumstances, but the architect, surveyor or engineer employed as the expert may not necessarily be responsible for the actual investigation, which may involve unusually critical site inspections, laboratory testing and extensive knowledge of building science in order to make a reliable diagnosis of the causes of the problems. Such investigations are the province of the building scientist, usually working in close cooperation with the architects, surveyors or engineers who are also engaged to give expert evidence. It is the thoroughness of these investigations that makes them so interesting and instructive, as they frequently disclose matters which would not be considered in normal structural surveys. It is this more detailed information that is presented in this book, in the hope that it will assist in better understanding of building problems.