We have been carrying out… as a matter of urgency, inspections to roof planks made of Reinforced Autoclaved Aerated Concrete (RAAC).
Our surveyors have been carrying out RAAC Inspections to various buildings in Birmingham and the West Midlands including Schools and Public Buildings, to date this has predominantly been in roof spaces.
What is RAAC ?
RAAC is a lightweight, ‘bubbly’ form of concrete commonly used in construction between the 1950s and mid-1980s. It is predominantly found as precast panels in roofs (commonly flat roofs, sometimes pitched) and occasionally in floors and walls.
Appearance & texture
RAAC panels can be light-grey or white in appearance, the underside of the panels will appear smooth. The inside of the planks will appear bubbly, often described as looking like an Aero bar. Unlike traditional concrete, there will not be visible stones (aggregate) in the panels.
Panel Size & Profile
RAAC panels are typically 600mm (approximately 2 feet) wide although this has been known to vary. Their length will vary, typically up to 6 metres. RAAC panels typically have a chamfer along their edge meaning there is a distinctive V-shaped groove every 600mm in the surface of the roof, floor or wall.
RAAC panels are very soft. If you press a screwdriver, screw or nail into the surface of a RAAC panel you will be able to make an indentation in them.
BE AWARE – if there is a surface covering to the panels you should not try to make an indentation as the covering may contain asbestos. Before any works are undertaken, the buildings Asbestos Register MUST be referred to.
On this occasion, under the guidance of a Structural Engineer, we carried out the following inspections.
- To scan 24 beam ends for bearing, void & reinforcement layout.
- Investigate 12 locations where two beams abut across a structural beam.
- To each beam delicately chase/expose a longitudinal bar to its end.
- To each beam end chase/expose the transverse/anchor/link rebar.
- Carry out a detailed visual/photographic condition survey recording the following:
- Deterioration including cracking or spalling, excessive deflection, and water ingress.