The discovery of potentially dangerous Reinforced Autoclaved Aerated Concrete (RAAC) in many schools, hospitals and other buildings across the country recently prompted massive public concern. The news that Colston Milton Parish Church, north Glasgow, had to close temporarily after RAAC was suspected in the building's panels has led to concern that other churches may have the same problem.
Evangelicals Now questioned Christian structural engineer James Miller about the implications for churches:
en: How prevalent is RAAC is church buildings in the UK?
It is most unlikely to be found in historic listed buildings, especially Grade I and II churches, because the quality of materials asked of modern work in these forms is much higher, and RAAC is a relatively inexpensive product - it would not have been permitted. It may, however, be found in late twentieth century churches, particularly those of a clean, simple design.
en: How about other structures such as church halls?
It is quite possible that it might be found in church halls and larger ancillary buildings dating from the 1960s to the 1980s, especially in buildings constructed under a ‘Design and Build’ contract. The material was favoured by contractors looking for quick system-build solutions for institutional buildings with a perceived limited lifespan, which is why it was so widely used in schools.
en: What parts of those building will be the worst affected?
These are likely to be the walls, ceiling and roofs - but only if these are relatively simple buildings. RAAC was not much used in small buildings, or those with complex patterns of windows; and almost never in small extensions.
en: What actions should churches take now if they suspect they might contain RAAC? Should they inform their insurers?
Don’t panic but do act responsibly. First, find out what your building is made of. The best people to do this are those in your fellowship who are most informed: building professionals or the builders themselves. Ask those with the longest memory how any recent, substantial new extensions were done. Find the design consultants and ask them. Failing that, do some investigations, opening small holes in the elements in question and looking for the reinforcement. And churches should check the small print of their insurance policies, too.
en: What will happen if they find it and do nothing?
RAAC is not necessarily going to fail immediately - but it is a potential risk. Once identified, the components ought to be inspected by a qualified structural engineer every five years. But it is a particular risk when it becomes damp, or if it has been overloaded; then, prompt action may be required. If you are very concerned because you know you have RAAC and these symptoms are present, arrange an immediate survey.
en: Roughly what sorts of costs might be incurred to fix/remove RAAC from eg a church hall?
RAAC components form the basic building-blocks of a structure. Removal is a fundamental change and will be very costly. But RAAC is not at all like asbestos – it is not a risk to human health and can be left in place. The risk is, instead, potential structural failure. It may be possible to strengthen the building without removing the RAAC, a more economic option.
en: Where should churches go for help, if they need it?
Their first stop should be their retained professionals: architects, engineers, or regional advisory committees. Every church that owns a building should have a group of people who oversee the fabric – they should work out where the risk lies. And for most, it is unlikely that there is any problem.
James Miller MA CEng FICE FIStructE Conservation Accredited Engineer, is a Chartered Engineer with over 40 years’ experience in the construction industry. He has worked on schools, hospitals and transport systems but now specialises in historic buildings and listed properties, including churches. He has led projects at Ironbridge, Kew, Wells Cathedral and Westminster Hall. He is a Reader in the Rochester Diocese.
