Willowbrook Mead Primary Academy in Leicester is among schools which have been forced to close (Picture: SWNS)

The new school year has been thrown into chaos for many parents and students after The Department for Education (DfE) ordered more than 100 schools to partially or fully close due to the presence of RAAC concrete – which is prone to collapse.

RAAC – a type of lightweight, bubbly concrete used in many public buildings from the 1950s until the 1990s, has a lifespan of around 30 years, which has led to safety concerns and suggestions from The Health and Safety Executive that structures ‘could collapse with little or no notice’.

More than 150 schools and colleges are actually impacted in total already – that’s because around 50 were already suffering from disruption this year and a further 104 have been added to the list.

With many having to undergo repairs to parts of their building – and in some cases close completely ahead of the start of term – repairing the problem could be a costly business.

With that in mind, how much has been spent on rebuilding schools over the past decade?

How much has been spent on improving schools with RAAC?

Schools Minister Nick Gibb has revealed that since 2015 the Government has spent around £15bn on improving schools.

That sum – which amoungs to £1.7bn a year – is known as ‘school capital funding’ and has been spent on ‘maintaining and improving the condition of school buildings and grounds’.

The DfE has spent a further £0.9bn a year on rebuilding schools, as part of the Schools Rebuilding Programme.

Abbey Lane Primary School in Sheffield is also among those named (Picture: PA)

However, it’s estimated they need a lot more than that, with the department saying in 2020 around £4bn would be needed for school maintenance over the following five years.

The DfE has been considering RAAC as a potential issue since late 2018.

National Education Union general secretary Daniel Kebede said: “It is absolutely disgraceful, and a sign of gross government incompetence, that a few days before the start of term, 104 schools are finding out that some or all of their buildings are unsafe and cannot be used.’

What is RAAC?

RAAC – which stands for Reinforced Autoclaved Aerated Concrete – is a type of lightweight, ‘bubbly’ concrete made from cement, lime, water and an aeration agent, which was used in buildings constructed between the 1950s and the 1990s

It’s usually found in roofs and occasionally in walls and floors.

It looks like normal concrete, but it’s weaker and less durable. RAAC was favoured in construction projects because of its lightweight thermal properties.

Experts say the building material is less durable than reinforced concrete and deteriorates over time, so is susceptible to sudden failure.

It has a life expectancy of little more than 30 years and this means buildings constructed from the 1950s to the 1990s that have not been checked by structural engineers are at risk of collapse.

RAAC is also prone to collapse when wet – which can happen if a building’s roof leaks.

The Standing Committee on Structural Safety (SCOSS) said in a statement: ‘Although called ‘concrete’, RAAC is very different from traditional concrete and, because of the way in which it was made, much weaker.’

As well as schools, RAAC has been used in a lot of other public buildings across the country – such as police stations, courts and hospitals.

MORE : A single beam triggered alarm about ticking time-bomb ‘Aero’ concrete that forced 100 schools to close

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Many are having to close buildings amid concrete safety concerns.