How Steel Frames Can Solve A Crumbly Concrete Problem
The issue of reinforced autoclaved aerated concrete (RAAC) is one many people and organisations have actually been dealing with for years, even if the issue of ‘crumbly concrete’ only hit the headlines when the start of term was disrupted in many schools as buildings were closed for safety reasons.
While the government scrambled to fix the situation with various ‘mitigations’ being put in place, it started to emerge how many other kinds of buildings were affected. Whether it was hospitals, council offices and other public sector buildings, or private sector buildings like offices and theatres, the problem was never one to be found on just one side of the school gates.
Once it was the case that RAAC was seen as an extremely useful material to use, because it was lightweight, had good thermal properties and was fire resistant. Sadly it is also porous and simply doesn’t stand the test of time.
From today’s perspective, it makes no sense that RAAC was seen so positively, given its relatively short lifespan of around 30 years. Yet it was, from the 1950s to the 1980s. There may be some relief in that, because it means there won’t be another generation of RAAC-affected buildings to fix years from now, but at this moment there is a real problem.
While some buildings may only need minor modifications and mitigations because only a small amount of RAAC is present, in some cases whole buildings may have to be replaced, which means temporary structures could be crucial in filling the gap while a new, permanent building is constructed from scratch.
Portal frame buildings can fulfil this role because they are quick to assemble, robust and also can handle bad weather, which is, of course, vital at any time in Britain but especially as in some cases, RAAC-affected buildings will need several months to be fixed and thus replacements will be needed over the winter.
Of course, a steel frame structure may not quite cut it in a setting where a particular level of luxury is needed, such as a theatre with its opulent interior. But many buildings could be right at the opposite end of the comfort scale where the RAAC issue may still apply.
For example, lots of agricultural buildings have concrete elements to them and where there may be RAAC, this could still pose a danger to anyone working there or even livestock kept inside.
While schools had to return survey data on whether they had RAAC in their buildings - the very fact that so many did triggered the crisis - the fact is it is simply not known how big the problem is right now. It may be that many thousands of buildings with a wide variety of uses and designs have it in.
The scale of the problem will also mean higher levels of demand for construction work to replace RAAC with alternatives, such as bricks, solid concrete or stronger roofing materials. That means getting the work done may not happen as fast as hoped.
With this in mind, it makes a lot of sense to look at a rapidly assembled steel frame structure as the best option over this autumn and winter, whether as a temporary structure or even as a strong and reliable permanent alternative.