RAAC (Reinforced Autoclaved Aerated Concrete), once a widely used construction material, has recently come under scrutiny due to safety concerns, especially in public sector buildings. If you’re unsure whether RAAC was used in your building, it’s important to understand the potential risks and the steps you may need to take—making it essential to consult the right structural engineer.
One of the main concerns with Reinforced Autoclaved Aerated Concrete (RAAC) in the UK is its limited durability, which can compromise structural integrity. RAAC planks contain internal voids that allow water to penetrate, leading to corrosion of the reinforcement. This can result in cracking, spalling, and, in severe cases, structural failure or collapse. These issues highlight the importance of thorough structural assessments and inspections to determine the condition of RAAC planks and ultimately prevent failures.
The survey process begins with a review of records and building control documentation to develop a clear understanding of the site. This is followed by an on-site inspection, where engineers examine the entire building to identify any RAAC elements and assess the extent of cracks, delamination, and reinforcement corrosion.
If RAAC is present, a risk assessment is carried out to provide guidance on the available options and recommended next steps. This process must always be undertaken in line with the guidelines of the Institution of Structural Engineers and current government directives.
RAAC was most commonly used in public sector buildings such as social housing, schools, universities, and healthcare facilities. It became popular due to its cost-effectiveness, versatility, and ease of installation, making it attractive for large-scale projects where efficiency and affordability were essential. Beyond these advantages, RAAC also offered benefits in terms of insulation and lightweight construction.
Discovering RAAC in a building can understandably cause concern. It is important to recognise that there is no single solution. In some cases, no immediate structural intervention may be necessary, although ongoing monitoring will be required. In others, full replacement with stronger, more durable materials may be the only viable option.
Alternative repair methods are available. For example, carbon fibre plating can be applied to strengthen RAAC elements. This material is lightweight, easy to install, resistant to corrosion, cost-effective, and, under certain conditions, offers a medium-term maintenance-free solution. Another approach is to introduce new steel beams between existing columns and beams to support RAAC planks, provided the original elements remain undamaged and dry.
Engaging the right structural engineer is essential when assessing RAAC in schools, hospitals, residential properties, or other buildings. As a leading structural engineering firm, our engineers are fully trained to provide RAAC surveys. If you suspect RAAC may be present in your building, please get in touch for an initial discussion on the next steps: 01794 524447.
AWA Consulting Engineers is a structural, civil, and marine engineering consultancy established in 1987, with a hard-won but deserved reputation for delivering excellence in our profession.
Our philosophy is simple: we put people first. This has resulted in a high number of repeat clients and an impressive track record of successful award-winning projects. We are proud to be professional, and approachable; we believe this makes us the ideal partner for your project.
AWA has technical teams in our offices located in Romsey, Hampshire and Bath, Somerset. We deliver services to clients typically across the South, South East and South West.
Our team includes both chartered structural engineers and chartered civil engineers committed to continuous professional development ensuring you benefit from up to date industry expertise, whatever your project entails.
To find out more about how AWA Consulting Engineers can help with your project, get in touch today. Email mail@awaengineers.com and one of the team will be in touch. Alternatively, call 01794 524447 to speak to a member of our team.
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