3 ms·

And this is one of the big issues with RAAC (Reinforced Aerated Autoclaved Concrete, extensively used in the UK in the 60s and 70s. The concrete is aerated (thi

And this is one of the big issues with RAAC (Reinforced Aerated Autoclaved Concrete, extensively used in the UK in the 60s and 70s. The concrete is aerated (think expanded polystyrene) so it is compressible. That means that you don't see any cracking on the surface as tye rebar corrodes. There is no obvious warning of imminent collapse. The panic in the UK last summer after RAAC ceilings in 2 UK schools collapsed (thankfully during the holidays) was because they had been recently inspected- one the week before.

defrost 2y ago
The social flow on effects spread even wider. Large numbers of low cost social housing used RAAC as a roofing solution that exists to this day. Councils that still manage low rent housing for people on assisted incomes are taking the financial hit for insurance and replacement. Arguably worse is the situation of those people who scrimped and saved and bought their way out of povety and purchased the house they previously rented. What was once an investment of their life savings into capital that would grow in value is now money lost in a house scheduled for demolition that has zero value with a defect no insurer will cover.