Reinforced autoclaved aerated concrete : The history and development of the product, its characteristics, uses and shortcomings

The media frenzy following the sudden closure of several schools in the summer of 2023 drew attention to the use of reinforced autoclaved aerated concrete (RAAC) in many public buildings in the UK, in turn spawning political debate as to why remedial action had not been taken sooner, whether chronic underinvestment was to blame, or whether successive governments had systematically cut corners by using cheap and short-life materials. Throughout this period the Royal Institution of Chartered Surveyors (RICS) and other professional institutions attempted to maintain a reasoned approach based upon factual analysis and developing knowledge as to the long-term performance of RAAC and the practical implications of its use. Despite poor experiences in the UK, RAAC has been, and still is, used extensively throughout Europe, the Americas and the Far East seemingly without the litany of failures identified in this country. This paper attempts to explain the history and development of the product, its characteristics, uses and shortcomings. Comment will be given on survey methodology, risk assessment and remedial works along with potential legal implications for surveyors and other practitioners.