What is RAAC and why is it a problem?

You might not have heard much about reinforced autoclaved aerated concrete (RAAC) until it made the news recently. Used in construction between the 1950s and 1990s, it’s a type of aerated concrete that became widely used – particularly for flat roofing, floors and walls – because it was lightweight, fairly low cost, and relatively quick to produce. Those properties made it popular, especially in education buildings where space was needed and budgets were (sometimes) low. 

Yet headlines lately have revealed that this was too good to be true. RAAC is less durable and behaves quite differently to traditional reinforced concrete. Its bubbled texture allows water to enter the material, exposing it to moisture. This can cause structural failure as the reinforcements can weaken and decay.  

Why are we facing issues with RAAC today?

The issue with RAAC is becoming a problem now because the material has a lifespan of around 30 years. That means many buildings, predominantly education facilities, where RAAC was used are now deemed to be unsafe. It’s been hugely disruptive and meant that many schools and universities have spent this last half term undergoing emergency building works, with pupils back to virtual schooling. 

Not only does this mean the situation is increasingly important, it’s also ever changing as new developments with RAAC are studied and uncovered week-on-week. Therefore, construction specialists – like our team here at Hawes Construction Group – need to use the knowledge we have and build on it as developments in RAAC are ongoing.  

How is Hawes Construction Group making a positive change?

As well as learning as much about RAAC as we can, we’ve been working alongside our client, the University of Sussex, on a RAAC panel replacement scheme at Bramber House – one of the university’s main hubs. The university commissioned a survey in 2022 and found Bramber House was one of five of their buildings that contained RAAC, and appointed Hawes Construction Group to remove the RAAC panels and replace them with timber. 

To do this, we needed to keep up with the RAAC situation as it evolved to understand how best to work with the material and make sure staff and students could access the building safely. This included initial, thorough assessment of how the RAAC panels had been laid, so we could work out which would be the safest way to remove them while minimising disruption for students and staff.  

It’s been a big project – expected to last 24 weeks – where we’ve worked alongside contractors carrying out other work across the university. The University of Sussex has been kind enough to let us talk about the work we’ve done with them. We’re thrilled they’ve been impressed by Hawes Construction Group’s ethics and approach, and we’re looking forward to sharing the case study soon.  

What happens next with RAAC construction?

The situation with RAAC is changing day by day. Yet, thanks to Hawes Construction Group’s experience, skillset and enthusiasm for learning, we have the knowledge and drive to stay on top of developments. That means we’re adapting to any changes that come our way, making sure we’re aware of any updates and techniques that allow us to react to our clients’ RAAC needs and respond quickly, and safely.  

Combining pride and professionalism, we’re always keen to support our fellow construction industry colleagues and our clients across the country. If you have a question about RAAC and need support to remove it with a safe and efficient approach that causes minimal disruption, our advice, guidance and operations are all here to help you.