RAAC Crisis: What You Need to Know

Introduction:

Reinforced autoclaved aerated concrete (RAAC) is a lightweight concrete that was used extensively in the construction of schools and hospitals in the UK from the 1950s to the 1990s. However, RAAC has been found to be susceptible to crumbling and cracking, which can pose a serious safety hazard.

In recent years, there have been a number of high-profile incidents of RAAC failure, including the collapse of a school roof in Kent in 2018. As a result, there is growing concern about the safety of RAAC-built buildings in the UK.

Recent News Updates and Information:

In September 2023, the UK government published a list of 147 schools and education settings in England that are known to contain RAAC. The government is currently working with these schools to assess the risks and develop remediation plans.

In the same month, the BBC reported that hundreds of other schools in England could still contain RAAC. The government has said that it is working to identify all RAAC-built buildings in the UK.

The RAAC crisis is also having an impact on the UK construction industry. Builders are finding it difficult to get insurance for projects involving RAAC, and the cost of new buildings are likely increasing with alternative material costs.

Impact on the UK Construction Industry:

The RAAC crisis is having a significant impact on the UK construction industry. Schools and hospitals that are made of RAAC are being closed or demolished, which is costing the government millions of pounds.

How to Mitigate the Damage Caused by RAAC:

The damage caused by RAAC can be mitigated by inspecting RAAC-built buildings regularly and taking steps to repair any damage that is found. In some cases, it may be necessary to replace RAAC with a more durable material.

Your company can help to mitigate the damage caused by RAAC by providing inspection and repair services for RAAC-built buildings. You can also educate the public about the RAAC crisis and the steps that can be taken to protect themselves.

What is RAAC?

RAAC is an acronym for reinforced autoclaved aerated concrete. It is a lightweight concrete that is made from cement, water, sand, and aluminum powder. The aluminum powder reacts with the water to produce gas bubbles, which give RAAC its lightweight properties.

RAAC was first developed in Sweden in the 1920s and became popular in the UK in the 1950s. It was used extensively in the construction of schools and hospitals because it is lightweight, strong, and fire-resistant.

How is RAAC Made?

RAAC is made by mixing cement, water, sand, and aluminum powder together. The mixture is then placed in an autoclave, which is a high-pressure, high-temperature chamber. The autoclave cooks the concrete, which causes the aluminum powder to react with the water and produce gas bubbles. The gas bubbles make the concrete lightweight and strong.

Why is RAAC Susceptible to Crumbling?

RAAC is susceptible to crumbling because of the aluminum powder in its composition. The aluminum powder can react with the moisture in the air to produce acids. These acids can attack the concrete and cause it to crumble.

The risk of RAAC crumbling is higher in buildings that are exposed to the elements, such as schools and hospitals. It is also higher in buildings that are poorly maintained or that have been damaged.

Conclusion:

The RAAC crisis is a major threat to the UK construction industry, and there’s a lack of clarity on just how far this reaches and the exact scope of the problem, public buildings? social housing? etc…

However, there are steps that can be taken to mitigate the damage caused by RAAC. By working together, we can ensure that RAAC-built buildings are safe and secure for everyone.

Additional Tips for Construction Companies:

• Educate your clients about the RAAC crisis. Help them to understand the risks and the steps that they can take to protect themselves.
• Offer inspection and repair services for RAAC-built buildings. This will help to ensure that RAAC damage is identified and repaired early.
• Consider using alternative materials to RAAC in new construction projects. There are a number of durable materials available that are not susceptible to crumbling.

By following these tips, construction companies can help to mitigate the damage caused by the RAAC crisis and build safer and more durable buildings.

For more detail, we found this informative video by a structural engineer. See below: