The crisis over unsafe concrete in schools may extend beyond the education sector to other types of public buildings, experts have warned.
They say the scale of the problem with reinforced autoclaved aerated concrete (RAAC) is “much bigger than schools” and could include hospitals, police stations, and court buildings.
Even private sector sites such as shopping centres and residential tower blocks could also be impacted, experts say.
Meanwhile, Labour MP Dame Meg Hillier, chairwoman of parliament’s Public Accounts Committee, has warned the issues with RAAC in schools are just the “tip of the iceberg” of maintenance issues for sites across England.
Labour has called for an “urgent audit” across the public sector estate, while the Liberal Democrats say the public must be given “urgent clarity” over whether hospital wards and buildings could also be forced to close.
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2:13
Concrete crisis explained
RAAC is essentially a lighter-weight form of concrete, used to build roofs, schools, colleges and other buildings from the 1950s until the mid-1990s,
But experts fear that the material has now reached the end of its shelf life and is liable to collapse.
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Though not confirmed, it is estimated that around 24 schools in England have been told to close entirely because of the presence of RAAC.
Schools minister Nick Gibb has admitted more could be asked to shut classrooms.
But the problem could be far wider than just schools, experts say, with other buildings at risk of “sudden and catastrophic collapse” if RAAC is not removed.
Chris Goodier, professor of construction engineering and materials at Loughborough University, said the “scale of the problem is much bigger than schools”.
What is Reinforced Autoclaved Aerated Concrete?
Reinforced Autoclaved Aerated Concrete – handily shortened to RAAC – is essentially a lightweight form of concrete.
It was used to build roofs, schools, colleges and other buildings from the 1950s until the mid-1990s, according to GOV.UK.
In comparison to traditional concrete, RAAC is weaker. It is made in factories using fine aggregate, with chemicals to create gas bubbles and heat.
Both the material properties and structural behaviour differs significantly from traditional reinforced concrete.
In 2019, the Standing Committee on Structural Safety highlighted the significant risk of failure of RAAC planks.
Three years later in 2022, the Office of Government Property sent a safety briefing notice to all property leaders, saying that “RAAC is now life-expired and liable to collapse”.
Chris Goodier, professor of construction engineering and materials at Loughborough University, said: “It is RAAC from the 1950s, 60s and 70s that is of main concern, especially if it has not been adequately maintained.
“RAAC examples have been found with bearings (supports) which aren’t big enough, and RAAC with the steel reinforcement in the wrong place, both of which can have structural implications.”
He says it could cover public sectors including health, defence, and justice, as well as some private sector buildings.
NHS providers have already identified 14 hospitals, which were constructed “either wholly or in major part with RAAC”. Seven of these are considered “critical” and not fit for purpose beyond 2030.
Three buildings operated by Police Scotland have also been found to contain RAAC after an investigation of 65 structures.
Matt Byatt, president of the Institution of Structural Engineers, says any high-rise buildings with flat roofs constructed between the late 1960s and early 1990s may also contain RAAC.
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9:18
‘New evidence’ to shut unsafe schools
According to Dame Meg, the DfE has been aware of a “significant problem” with RAAC since a roof collapse in 2018.
She warns that this week’s announcement could have a “significant impact” on the department’s wider school maintenance programmes.
In an opinion piece in The Times newspaper, she writes: “At our hearing in July it was clear that officials were being thorough with the proportion of school buildings they were working on, including the surveys of 600 schools with RAAC which have led to this week’s decision.
“But this is the tip of the iceberg of a failing school estate in England. Most of the 700,000 pupils currently being educated in substandard buildings are not in RAAC buildings and will now be waiting longer for the improvements they need.”
Image: A taped-off section inside a school affected by reinforced autoclaved aerated concrete (RAAC)
Image: Damage inside Parks Primary School in Leicester which has been affected with sub standard reinforced autoclaved aerated concrete (RAAC)
Around 104 schools or “settings” in England found with concrete prone to collapse are set to be closed or disrupted – on top of 52 that have already been affected this year.
The government says the schools needed to close because of safety fears, which have arisen due to concrete failing “with no warning”.
While the DfE has previously focused on remediation, Mr Gibb says the department is now taking the “cautious approach” that all of the concrete should be removed.
There is “no doubt” the UK “will spend 3% of our GDP on defence” in the next parliament, the defence secretary has said.
John Healey’s comments come ahead of the publication of the government’s Strategic Defence Review (SDR) on Monday.
This is an assessment of the state of the armed forces, the threats facing the UK, and the military transformation required to meet them.
Prime Minister Sir Keir Starmer has previously set out a “clear ambition” to raise defence spending to 3% in the next parliament “subject to economic and fiscal conditions”.
Mr Healey has now told The Times newspaper there is a “certain decade of rising defence spending” to come, adding that this commitment “allows us to plan for the long term. It allows us to deal with the pressures.”
A government source insisted the defence secretary was “expressing an opinion, which is that he has full confidence that the government will be able to deliver on its ambition”, rather than making a new commitment.
The UK currently spends 2.3% of GDP on defence, with Sir Keir announcing plans to increase that to 2.5% by 2027 in February.
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This followed mounting pressure from the White House for European nations to do more to take on responsibility for their own security and the defence of Ukraine.
The 2.3% to 2.5% increase is being paid for by controversial cuts to the international aid budget, but there are big questions over where the funding for a 3% rise would be found, given the tight state of government finances.
While a commitment will help underpin the planning assumptions made in the SDR, there is of course no guarantee a Labour government would still be in power during the next parliament to have to fulfil that pledge.
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From March: How will the UK scale up defence?
A statement from the Ministry of Defence makes it clear that the official government position has not changed in line with the defence secretary’s comments.
The statement reads: “This government has announced the largest sustained increase to defence spending since the end of the Cold War – 2.5% by 2027 and 3% in the next parliament when fiscal and economic conditions allow, including an extra £5bn this financial year.
“The SDR will rightly set the vision for how that uplift will be spent, including new capabilities to put us at the leading edge of innovation in NATO, investment in our people and making defence an engine for growth across the UK – making Britain more secure at home and strong abroad.”
Sir Keir commissioned the review shortly after taking office in July 2024. It is being led by Lord Robertson, a former Labour defence secretary and NATO secretary general.
The Ministry of Defence has already trailed a number of announcements as part of the review, including plans for a new Cyber and Electromagnetic Command and a £1bn battlefield system known as the Digital Targeting Web, which we’re told will “better connect armed forces weapons systems and allow battlefield decisions for targeting enemy threats to be made and executed faster”.
Image: PM Sir Keir Starmer and Defence Secretary John Healey on a nuclear submarine earlier this year. Pic: Crown Copyright 2025
On Saturday, the defence secretary announced a £1.5bn investment to tackle damp, mould and make other improvements to poor quality military housing in a bid to improve recruitment and retention.
Mr Healey pledged to “turn round what has been a national scandal for decades”, with 8,000 military family homes currently unfit for habitation.
He said: “The Strategic Defence Review, in the broad, will recognise that the fact that the world is changing, threats are increasing.
“In this new era of threat, we need a new era for defence and so the Strategic Defence Review will be the vision and direction for the way that we’ve got to strengthen our armed forces to make us more secure at home, stronger abroad, but also learn the lessons from Ukraine as well.
“So an armed forces that can be more capable of innovation more quickly, stronger to deter the threats that we face and always with people at the heart of our forces… which is why the housing commitments that we make through this strategic defence review are so important for the future.”