Recent queries about the potential use and risks associated with reinforced autoclaved aerated concrete (RAAC) in Ministry of Defence buildings have brought the issue to public attention.
This concern emerged in response to written parliamentary questions posed to the MoD.
Question by Luke Pollard, Shadow Minister (Defence): “To ask the Secretary of State for Defence, whether the presence of reinforced autoclaved aerated concrete (RAAC) in buildings on the defence estate was included in his Department’s risk register.”
Question by Luke Pollard, Shadow Minister (Defence): “To ask the Secretary of State for Defence, how many and what proportion of buildings used by British service personnel overseas have reinforced autoclaved aerated concrete (RAAC) present in their construction.”
Question by John Healey, Shadow Secretary of State for Defence: “To ask the Secretary of State for Defence, how many schools operated by the Defence Children’s Services were constructed using reinforced autoclaved aerated concrete (RAAC).”
Question by John Healey, Shadow Secretary of State for Defence: “To ask the Secretary of State for Defence, whether any Defence Children’s Services buildings will be closed because of the presence of reinforced autoclaved aerated concrete (RAAC).”
Response by James Cartlidge, The Minister of State, Ministry of Defence, to the questions reads:
“The Ministry of Defence has indicated that it will not be possible to answer this question within the usual time period. An answer is being prepared and will be provided as soon as it is available.”
The mounting concerns surrounding RAAC have been accentuated by expert warnings. Several government and private buildings across the UK have been identified as needing urgent safety checks due to the use of deteriorating RAAC concrete.
This revelation came from a Loughborough University team, with Professor Chris Goodier remarking, “We’ve suddenly found out that a certain proportion of our building stock is not as good as we thought it was.”
Historically, RAAC’s structural integrity became a topic of discussion in the 1990s. The alarm bells became louder after a roof collapse at Singlewell primary school in 2018 and the UK Government Property Agency’s 2022 announcement, labelling RAAC as “life-expired and liable to collapse.”
2023 saw several significant incidents and closures related to RAAC’s potential dangers. This includes the closure of over 100 school buildings, public remarks from officials, and a host of safety checks on a vast array of structures.
Good Lord 🙄 👷
“I refer the honourable gentleman to the answer I gave on the Today Programme on Wednesday.”
RAAC will be everywhere. The problem is actually that the buildings are being used well after their anticipated expiry date like most of the Schools.
Did HMG really expect a school to only last 30 years, and then be demolished and a new building erected with RAAC again used in its construction?
Hi Graham. Local Authorities historically built Schools. They would do that based on projected housing growth which left them scrambling to provide places in the boom times such as the sixties. Often, for smaller communities they would provide pre-fabricated simple hut type buildings with little or no foundation. Many of those buildings are still in use. Secondary Schools would normally be simple cheap two or three storey designs trying to make the most of the Government grants. Building to last was not the objective.Local Authorities might write off the cost over as little as 25 years.
The thing about Schools was the need to act in the interests of the current students and provide for their education given the money you have available. If RAAC at the time of building was within building regs and there were no known problems then you can see why it was attractive to local authorities. On this site we discuss building kit which might only last a short period of time. Nothing lasts forever especially if not maintained.
I remember in the 1970s when we had a similar crisis over High Alumina Cement and many schools closed down for rebuilding. Afterwards they renamed it Calcium Aluminate Cement. What do we think they’ll rename RAAC as?
Hi Mark, Thanks. I was a pupil (or a student as they would now say of an 11-year-old!) of Thomas Bennett Comprehensive School, Crawley, the largest school in the country in the 1960s.
We were often educated in wooden huts built in line with the rapid growth of Crawley. I think they had a theoretical life of 10-15 years – they were used for well over 30 years!
OT: IFR – International Federation of Robotics released the data for 2021 on industrial robots per 10000 workers manufacturing industry
South Korea: 1000
Now follows Euro country numbers only
Germany: 397
Sweden:321
Slovenia:249
Switzerland:240
Denmark:234
Netherlands: 224
Italy: 217
Belgium+Lux:198
Austria: 196
Czech Rep: 168
Spain: 167
France 163
Finland :161
UK is below the threshold of 22 first in the world so do not appear in the list.
China: 322
USA: 274
I’m kind of surprised that, as it is generally a tensile mode of failure, that carbon fibre adhered to the underside isn’t used as an in situ fix?
Even the beams can be encased. Saves stripping the whole thing apart.
Also provides a crash net if a single concrete plank fails.
Carbon fibre matting, of the grades needed here, isn’t that expensive.
A lot if the issue comes due to poor maintenance and leaky flat roofing with old felt and bitumen roofing. That caused corrosion in the reinforcement.
Now with fibreglass and single ply membranes they can be fixed quite readily.
Roman concrete lasts thousands of years. Our RAAC 30 years. Go figure. Shameful short sightedness. HMG should never have stopped/delayed replacement.