22,000 homes in Aberdeen are being checked for RAAC, with around 500 already believed to have been built using the lightweight building material.
Aberdeen City Council has revealed that reinforced autoclaved aerated concrete, otherwise known as RAAC, may have been used in thousands of council houses.
The news comes just weeks after it came to light that RAAC had been found in a number of schools in the region.
The bubbly form of concrete has been used in around 500 Balnagask homes, predominantly found as precast panels in roofs and commonly found in flat roofs, as well as occasionally in floors and walls.
An Aberdeen City Council spokesperson said: “We are liaising with tenants, private owners and occupiers, and landlords as a matter of priority.
“We will continue to keep residents informed and update our website with the latest information.”
What is RAAC?
The material was commonly used between the 1950s and 1990s as a cheaper alternative to conventional reinforced concrete.
RAAC is aerated, bubbly and has often been described as looking like an Aero bar.
However, it's far less durable than reinforced concrete and only has a lifespan of around 30 years.
It is also susceptible to structural failure when exposed to moisture. The bubbles can allow water to enter the material.
If that happens, any rebar reinforcing RAAC can also decay, rust and weaken.