Reinforced Autoclaved Aerated Concrete (RAAC): A Structural Risk You Can’t Ignore
In recent years, Reinforced Autoclaved Aerated Concrete (RAAC) has made national headlines because of unexpected failures in public and residential buildings.
If your building was constructed or refurbished between the 1950s and 1990s, it could contain RAAC planks in roofs, floors or wall panels and this may pose a serious safety risk.
For owners and Principal Accountable Persons (PAPs) of Higher-Risk Buildings (HRBs), residential blocks over 18 metres or seven storeys, the Building Safety Act 2022 places a legal duty to identify and manage structural failure risks. RAAC is now a priority concern.
What Is RAAC and Why Is It Problematic?
- Lightweight, air-filled concrete: RAAC was popular from the 1950s to the 1990s because it was quick to install and cost-effective.
- Lower strength and durability: Unlike dense reinforced concrete, RAAC is porous, retains moisture and is prone to deterioration over time.
- Unexpected failures: When RAAC planks degrade, they can fail suddenly without obvious warning signs, making them a major concern for safety regulators.
Where RAAC Might Be Found
- Flat roofs and roof decks: Often used as lightweight planks spanning between beams.
- Floor slabs in schools, offices and some residential blocks.
- Wall panels or infill panels in mid-century construction.
Buildings built or altered between the 1950s and 1990s are most at risk. If you’re unsure about your structure’s materials, a targeted structural inspection is essential.
The Regulatory Context for RAAC
- The Building Safety Regulator (BSR) expects owners to demonstrate they have identified all significant structural risks.
- The Department for Education and other government bodies have already highlighted RAAC failures in public buildings, increasing regulatory scrutiny.
- Failure to address RAAC could delay your Building Assessment Certificate (BAC) and expose you to enforcement action or liability.
What Building Owners Should Do
- Commission a structural safety inspection: A competent engineer can confirm if RAAC is present by reviewing records and carrying out non-intrusive or targeted opening-up investigations.
- Assess condition and risk: Engineers evaluate RAAC’s structural performance, moisture levels and visible deterioration.
- Plan remediation or monitoring: If RAAC is found, options include strengthening, replacing, supporting or carefully monitoring elements while planning longer-term remediation.
- Document findings in your Safety Case: Evidence must be stored in your Golden Thread and included in your Structural Safety Report (SSR).
How Structures Made Easy Helps
At Structures Made Easy, we help owners and asset managers tackle RAAC risk with:
- Chartered Structural Engineer-led inspections focused on RAAC identification and risk assessment.
- BSR-ready Structural Safety Reports that document RAAC findings clearly for regulators.
- Practical advice on temporary supports, strengthening or replacement strategies.
- Fast turnaround and portfolio pricing for clients with multiple HRBs.
- Digital-ready reporting to integrate into the Golden Thread.
We make RAAC risk management clear, compliant and action-focused, helping you keep residents safe and avoid regulatory delays.
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