Raac and ruin? What the concrete crisis means for UK politics
British politics has returned from the summer obsessed with one apparently unlikely subject concrete. So what is reinforced autoclaved aerated concrete, or Raac, and why is it suddenly so prominent?
What is Raac?
Also known variously as aerobar and aircrete, the aerated in the Raac acronym means the concrete is bubbly, rather than filled with material, such as gravel or crushed stone. This makes it cheaper to produce, more lightweight and easier to install but, crucially, also less durable, with a limited lifespan of about 30 years.
Pioneered in Sweden, Raac was widely used in the UK from the 1950s to the 1980s, and in some cases into the 1990s, often in schools and other public buildings. It was mainly used for roofing, but also for walls and floors.
Why are we suddenly hearing so much about it?
Because at the end of last week, days before the start of the new academic year, an urgent alert went out about the potential risks from Raac-built schools around England, with 156 identified initially as a concern.