Introduction

For most advanced economies, building construction represents one of the largest, if not the largest, single investment of national resources. The wellbeing of such economies is therefore heavily dependent upon the satisfactory performance of its construction. Failures in the built environment occur for a variety of reasons and on a variety of scales. In macroeconomic terms, the small domestic structure which burns to the ground because of a fire started in play by children is insignificant when compared with a national disaster such as a major earthquake, affecting a million people simultaneously. There are less obvious types of failure which can also cause widespread human distress and be of considerable economic significance, such as problems occurring in populations of system-built construction where many thousands of units have to be considered as unsatisfactory as a result of a few actual failures. Examples of this phenomenon of population failure have occurred in the UK in large-panel system-built housing (BRE, 1985; 1986; 1987) and in long-span school and leisure halls (Bate, 1974; 1984; DoE, 1974) amongst others.