Portable Buildings – The Answer To The RAAC Crisis

The latest hot topic on the news has been all about the RAAC crisis which has meant many schools have had to remain closed at the end of the summer break, with students forced to start the year by remote learning. What is slightly shocking is the fact the government has known about the problem for over thirty years, but it hasn’t been acted upon until now. But what is RAAC? And how will it affect people? And what is the answer? This blog will look at some of these questions.

What is RAAC?

RAAC, or Reinforced Autoclaved Aerated Concrete, is a building material with no coarse aggregate which was very popular in the construction industry between the 1950s and 1990s. It’s made by adding a foaming agent to a concrete mix, which is allowed to set and cure in an autoclave (a high-pressure steam chamber) – producing a cellular structure with small, non-connected air pockets. It basically looks like a giant, concrete Aero bar and consists of 80% air. To give panels more strength and durability they were often reinforced with steel meshes or bars.

What was RAAC used for?

The panels RAAC was used to create were made into flat roofing, flooring and wall panels. It was a very popular material as it was quick to produce, easy to install and cheaper than standard concrete as a construction material. It was, therefore, used in thousands of buildings, including schools, hospitals, court buildings, prisons and more. RAAC also has reasonable fire resistance and sound insulation properties which only added to its popularity. However, it has a ‘shelf-life’ and almost all of the applications have passed this time when it needed to be replaced and the concerns have been growing.

What is the problem with RAAC?

The long-term durability of RAAC begins to be an issue when the steel reinforcement inside begins to corrode and cause a reduction in structural integrity. The Institute for Structural Engineers flagged the issue as far back as 1961 when they recognised that moisture entering the bubbles of the concrete would reduce its strength and cause the material to decay, rust and weaken. The HSE flagged it as an issue as when it passes beyond its lifespan, it can collapse with little, or no, notice. The warning bells began when the roof of a staff room at a primary school in Kent suddenly collapsed – fortunately on a Saturday – in 2018.

Schools have been monitoring the parts of their buildings with RAAC, and concerns over the potential risks of collapse caused many schools to remain closed at the start of this academic year. The Department for Education estimates that funds need to be found to rebuild 300-400 schools as the governments of the last twenty years have not prioritised fixing this sleeping issue until now.

The latest figures seem to suggest that 7 court buildings, 24 hospitals and 156 schools are currently at the highest level for risk of collapse.

Raised flower beds outside a cream coloured building.

How can MPB help with the RAAC crisis?

Midlands Portable Buildings has been installing modular classrooms for nearly two decades. Schools often need additional space for larger year intakes or additional curriculum needs and MPB has been helping schools to find these extra classroom spaces since they began trading. A portable classroom is a temporary building that is designed to fulfil all the uses of a traditional school building. Able to be connected to water, electricity and sewage to allow for toilets, showers and more. They can be in place in a fraction of the time – and at a very competitive rate.

Quick to install

Modular buildings, or portable cabins, are a quick and cost-effective answer to many sudden accommodation issues. A traditional building project – such as the replacement of the RAAC panels in some schools is not a quick-fix project. Whilst the ongoing work causes disruptions to the everyday working of the school, a temporary classroom can allow it to function almost seamlessly.

Schools have had enough disruptions in the last few years with Covid and this latest issue seems to threaten further upsets to the education of thousands of young people up and down the country. To save this disruption, you can have modular classrooms installed in a matter of weeks, giving your students and teachers smart, comfortable and spacious new learning spaces to continue working seamlessly in – freeing you up to get the RAAC issues sorted in your main building. As we can create or modify your modular classroom at the same time as our onsite team prepares the groundwork, the lead times for having our classrooms in place are massively quicker than a traditional building.

Used or hired options

We also offer used modular buildings at a much cheaper rate than a brand new classroom, and they can be modified in exactly the same way. Modular buildings can be removed when they’re no longer needed and MPB will even buy back your modular classroom if it is in good condition – although you may find your new teaching space becomes a favourite and your school may opt to keep it even after the building work is completed. Another budget-friendly option is to hire one for the duration of any building work, so using a portable building may not be as expensive as you might think.


Every modular building from MPB is able to be customised to your needs – meaning your staff and students won’t even miss their old classrooms. We specialise in creating the custom-built spaces that schools need, with energy-saving LED lighting, timed heating and air conditioning.

Find out more

For more information about how a modular classroom, changing room, toilet block or office could help your school out while dealing with RAAC in your building, get in touch today to chat with a member of our friendly, expert team and receive a free, no-obligation quote.

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