Raac

What Is RAAC?

RAAC stands for Reinforced Autoclaved Aerated Concrete — a lightweight, aerated form of precast concrete that was widely used in construction from roughly the 1950s through the 1990s, most commonly in flat roofs, floors and wall panels of schools, hospitals, offices and other public buildings. It was popular because it was cheap, light and thermally insulating.

Unlike traditional dense concrete, RAAC is highly porous and contains very little aggregate. Steel reinforcement bars were often placed only in the lower section of the panels and were frequently not protected against corrosion. Over time, moisture ingress can corrode the reinforcement, and the material itself can lose strength — meaning panels may deflect, crack or, in the worst cases, fail suddenly with little visible warning. That is why RAAC has become a major focus of building safety assessments worldwide, and why locating, inspecting and monitoring affected buildings is now a priority for asset owners and facility managers.

How RAAC Is Assessed and Monitored

Because RAAC can deteriorate inside the structure, assessment relies on a combination of visual surveys, intrusive inspection, and increasingly on continuous structural monitoring. Teams use:

• On-site survey kits — rugged laptops, tablets and mini PCs paired with borescopes, laser scanners and thermal cameras to capture and record defects.

• Structural health monitoring (SHM) nodes — vibration, tilt, crack-width and humidity sensors that log data from roofs and ceilings over months or years.

• Edge computing gateways — fanless industrial computers that sit in plant rooms or ceiling voids, collecting sensor data and forwarding it to the cloud or a building management system.

Because much of this equipment is installed in dusty, humid or temperature-variable spaces above ceilings and in roof voids, fanless, dust-resistant, wide-temperature industrial computers are the usual choice over consumer-grade PCs.

Typical Technical Requirements