RAAC is a building material used in some buildings to form roof planks, wall panels, and sometimes floor planks, between the mid-1950s and mid-1990s.
If properly designed, manufactured, in good condition and with good bearing, RAAC installations are considered safe. However, the panels can creep and deflect over time, and this can be exacerbated by water penetration. A more recent incident indicated that if they have insufficient bearing and their structural integrity is compromised, they can fracture and collapse with little or no warning.
The Institution of Structural Engineers (IStructE) have issued guidance about RAAC to enable building managers and their consultants to manage the situation, established a RAAC working study group, and created a list of professionally qualified structural engineers (Chartered or Incorporated Members) who have declared their experience in providing technical solutions for managing RAAC planks.