According to the Concrete Society[1], these panels consist of autoclaved aerated concrete (sometimes called Aerated concrete) reinforced to form structural precast units. RAAC are made of the same core material as unreinforced autoclaved aerated concrete – cement, blast furnace slag, pulverised fuel ash or silica flour, and these are mixed with water and aluminium powder – invented in the 1920’s in Sweden, and introduced to the UK in late 1950’s. Concerns over the material and its use started in the 1980’s, as according to the Royal Institute of Chartered Surveyors (RICS)[2], when RAAC planks were not considered durable material and its life expectancy was predicted to be around 30 years by Building Research Establishment (BRE).
As the life span of RAAC is achieving its final expectancy, the government is worried with future failure of panels, exposing risks of collapse and damages. So far, over 150 schools have been identified as containing RAAC, and the minority have a mitigation plan in place.
The PII market is also following these developments closely. Surveyors are probably the first affected, being appointed to run maintenance inspections and surveys. Moreover, RICS calls for extra attention following the alert issued by Standing Committee on Structural Safety (SCOSS) about the collapse of a school roof in 2018[3]: - “whereas BRE used to advise that the material would show signs of failure over a period of time, the sudden failure reported by Standing Committee on Structural Safety suggests that surveyors may need to be more alert”.
Naturally, underwriters will scrutinise any surveyor exposure related to any work related to this subject and will expect a clear policy to bid/not bid for such projects and robust risk assessment on them. On the other hand, as RAAC was most used in construction from 1950 until mid-1990; therefore, any legal proceeding against contractors and designers is unlikely at this point. However, underwriters may want to know if they were ever included in their insured’s projects and when they stopped using them.
