Emergency RAAC Mitigation & Waterproofing

Project Challenges

The client’s roof had been identified as “fragile,” meaning standard foot traffic or traditional roofing methods would pose a catastrophic risk of deck failure. The objective was to create a rapid-cure waterproof barrier to arrest further decay while a permanent structural carbon-fibre beam strengthening design was finalised.

RAAC is a lightweight, “bubbly” form of concrete used widely from the 1950s to the 1990s. Its porous nature makes it highly susceptible to water-driven corrosion of the internal steel reinforcement. Once the internal “rebar” begins to degrade, the structural integrity of the planks is fundamentally compromised.

Safety-First Access

The primary challenge of RAAC works is the inability to walk directly on the surface. Balmore Group deployed a multi-layered safety and load-distribution strategy to protect both the technicians and the asset.

Integrated Protection Measures

Internal Crash Decking: We installed heavy-duty scaffolding internally. This “crash deck” acts as a secondary failsafe to support the structure and protect personnel working below in the event of a plank failure.

Safety Netting: High-tension netting was rigged to provide fall-arrest protection, essential when dealing with fragile substrates.

Easi-Dec Roof Walk System: To distribute weight across the RAAC planks, our team utilized the Easi-Dec system. These specialised walkways allow for safe movement by spreading the load across multiple structural points, ensuring the fragile deck remains unstressed.

MEWPs (Mobile Elevated Work Platforms): Where possible, we utilised booms and scissors to provide external access, minimising the time spent by technicians on the roof surface.

Liquid Roofing Systems

When a roof is too fragile for heavy bitumen boilers or mechanical fixings, Liquid Applied Membranes are the industry gold standard.

Balmore Group utilised a Rapid Roof Liquid System. This cold-applied solution provides several critical benefits for RAAC mitigation:

1. Lightweight Profile: Unlike felt or gravel, liquid membranes add negligible weight to an already stressed structure.

2. Fully Bonded & Seamless: It creates a monolithic “skin” over the RAAC, ensuring no water can track underneath.

3. Cold Application: No “hot works” (torches/flames) were required, significantly reducing fire risk on a sensitive site.

This temporary barrier provides a critical window of 12–24 months of total weather-tightness, allowing the structural engineers to complete the carbon fibre beam strengthening designs without the threat of ongoing water damage.

Bio-Monitoring & Bat Surveys

As this asset is situated in a sensitive rural location, the project was subject to strict ecological oversight.

Under UK law, protected species—specifically bats—frequently roost in the crevices of older industrial and infrastructure buildings. Balmore Group integrated environmental checks into the daily site workflow:

• Pre-work Inspections: Every section of the roof and eaves was inspected before work commenced to ensure no nesting birds or bats were disturbed.

• Eco-Compliant Timing: Our team coordinated works to ensure minimal noise and light pollution impact on the surrounding rural habitat.

Critical Infrastructure Expertise

Maintaining the operational status of critical infrastructure during a structural crisis requires a contractor who understands the high stakes. This project demonstrates our ability to act as a principal contractor who manages every facet of a high-risk site.

Why clients trust Balmore Group for RAAC Mitigation

Expert Access Knowledge: We don’t just use scaffolding; we design load-distribution solutions for fragile environments.

Speed of Response: Liquid roofing allows for “Rapid-Roof” results, stopping the clock on structural decay.

Holistic Compliance: From HSE-standard fall protection to environmental wildlife checks, we manage the red tape so the client doesn’t have to.

With the temporary waterproofing now successfully in place, the structure is stable and dry. This has allowed the design team to move forward with carbon fibre reinforcement, which will be applied to the underside of the RAAC planks to provide a permanent, high-strength structural upgrade.

Is your facility affected by RAAC?

If you have identified RAAC within your property portfolio, time is of the essence. Water ingress is the single greatest catalyst for RAAC failure. Balmore Group provides the specialised access and waterproofing solutions required to stabilise your asset while long-term remediation is planned.