Understanding RAAC Concrete Risks: Why Commercial Buildings Need Specialist Testing

In recent years, Reinforced Autoclaved Aerated Concrete (RAAC) has emerged as a serious concern in the UK property sector. Although used widely from the 1950s through the 1990s, RAAC is now known to be less durable than traditional concrete (especially under moisture exposure), making buildings that contain it vulnerable to sudden structural failure.

For commercial property owners, managers and stakeholders (such as those overseeing HMOs, schools, churches and community buildings), understanding and mitigating RAAC risk is critical. At Alpine Surveys, we specialise in independent structural investigations, helping you to identify RAAC, assess risk and plan remedial strategies.

What Is RAAC? And Why Is It a Problem?

RAAC is a lightweight, aerated form of concrete reinforced with steel. It was attractive to builders in its day because it was cheaper, easier to produce and quicker to install. However, these advantages come with trade-offs: RAAC typically has a limited service life (estimated around 30 years) and degrades significantly when exposed to water.

Water ingress through the porous, “bubbly” structure can corrode internal reinforcement bars, causing internal expansion and cracking and because of this, RAAC panels can fail without much warning, posing a real safety risk.

Which Buildings Are Most at Risk?

While RAAC has been found in a variety of building types, some of the most common at risk properties include:

• Schools: many educational buildings built between the 1960s and 1980s have RAAC roof planks, walls or floors.
• Churches and community halls: large span roofs were sometimes framed using RAAC.
• HMOs (houses in multiple occupation): especially where older communal areas or flat-roof extensions were built during the boom years.
• Public or institutional buildings: libraries, hospitals, offices from the post war period may also contain RAAC.

Given the age profile and construction era of many such buildings, owners and managers must seriously consider whether RAAC testing should be part of their risk management plan.

The Role of Structural Surveying: How Alpine Surveys Can Help?

As a specialist independent surveying company, Alpine Surveys brings decades of building surveying and structural engineering expertise to RAAC risk assessment. Here’s how we can support you:

1. Initial Screening & Site Visit

Before any in-depth testing, we conduct a thorough site inspection. Our qualified structural engineers assess the building’s age, construction drawings (if available) and visible signs that may indicate RAAC panels. For example, precast panel joints, unusual panel dimensions or roof light details. These inspections are supported by the latest survey technology, including thermal imaging, micro bore inspections and aerial drone surveys where needed.

2. Material Identification & Sampling

If the initial inspection raises concerns, we start with a non-destructive visual inspection and if necessary, invasive sampling will be undertaken. These are analysed to confirm whether the material is RAAC, how it is behaving (e.g. signs of water ingress, reinforcement corrosion) and whether any reinforcement is intact.

3. Structural Assessment & Risk Analysis

Our structural engineers evaluate the condition of identified RAAC elements. We assess load paths, support conditions and deterioration. If RAAC panels are compromised, we analyse whether there is an immediate safety risk or whether phased mitigation can be safely adopted.

4. Detailed Reporting

Once the assessment is complete, Alpine Surveys prepares a detailed structural survey report. Our reports provide:

• A clear description of any RAAC located
• Photographic and measured evidence
• An analysis of risk (short-term and long-term);
• Recommendations for remedial action
• Indicative cost guidance
• A plan for monitoring or repair, prioritised by urgency.

This aligns with the depth of reporting typically found in our structural building survey services.

5. Remediation Design & Monitoring

If remedial works are needed, our in-house structural team can design and calculate appropriate interventions: strengthening, replacement or support. We can also set up movement monitoring (e.g. crack gauges, displacement monitoring) to track performance over time.

6. Certification & Compliance Advice

For regulatory or funder requirements, we can provide Certificates of Structural Adequacy, giving you documented assurance of safety and compliance.

Why Choose Alpine Surveys for RAAC Testing?

There are several reasons that building owners trust Alpine Surveys with RAAC testing and structural surveys:

1. Independent and Unbiased: We are not affiliated with lenders or contractors, so our surveys and recommendations are impartial.
2. Highly Qualified Team: Our engineers hold advanced degrees (MSc, PhD) and have over 30 years of experience.
3. Comprehensive Technology: From drone inspections to thermal imaging and micro bore techniques, we apply the latest tools for accuracy.
4. Clear, Actionable Reports: We deliver in-depth reports with clear risk assessments and costed recommendations, not just observations.
5. Customer Care: Clients consistently praise our professionalism, communication, and responsiveness.

Practical Steps for Building Owners & Managers

If you manage or own a commercial property such as an HMO, school, or church and are worried about RAAC, here’s a practical roadmap:

1. Commission a Structural Survey: Ask for a survey that explicitly checks for RAAC, not all structural engineers will automatically look for it.
2. Prioritise Based on Risk: Use the survey findings to classify areas into high, medium or low risk.
3. Plan Remediation: Based on the report, carry out necessary strengthening or panel replacement. Consider monitoring for less urgent areas.
4. Budget & Phasing: Work with your consultant to phase work in a cost effective but safe way.
5. Maintain & Reassess: Even after remediation, periodic inspections (every few years) help ensure that RAAC risk remains under control.

Don’t Let RAAC Be Your Blind Spot

RAAC is not just a historic material, it is a structural risk that continues to threaten certain buildings, particularly older commercial ones. Left unchecked, it can lead to sudden and dangerous failure. At Alpine Surveys, we offer a full suite of services (from RAAC identification and testing to remediation design and monitoring) designed specifically for commercial and community buildings.

To discuss RAAC testing tailored to your property, visit our structural surveys page on our website or call us on 0330 333 9238. Together, we can manage RAAC risk responsibly and ensure that your building remains safe and compliant for the long-term.