Reinforced autoclaved aerated concrete (RAAC)

There has been much in the press lately about the presence of RAAC in schools. It can also be found in housing although SAL understands that its use in housing is not widespread.

RAAC was used in the construction of some buildings from the mid 1950s to the mid 1990s. If members own property in buildings constructed during this timeframe they should be alert to the possibility that RAAC may have been used in the construction. 

If RAAC is known to be present or property owners are uncertain about the construction materials used in their building it would be good practice to have a survey carried out to check for the presence of RAAC and the condition of any found. Of particular concern would be flat roofed properties where RAAC is more likely to be present and, if it is present, it is more likely to be at risk of structural damage from water penetration.

There is further guidance at https://www.istructe.org/resources/news/istructe-statement-reinforced-autoclaved-aerated-c/