The good news? Raac isn’t always dangerous. The bad news: it’s not just in schools

Events have moved rapidly since the Health and Safety Executive announced on Thursday that Raac concrete was now “life-expired”, and “liable to collapse with little or no notice”. The Department for Education (DfE) has moved to close more than 100 schools that contain the material, citing fears about safety ahead of the present academic year. And politicians, the public and the media are trying to get answers about how such a serious safety situation could have developed seemingly from out of nowhere.

As a professor of construction engineering and materials at Loughborough University, I’ve been studying Raac in buildings in Britain – mainly in the NHS – for several years now. It has been on many people’s radar for a while. Over the past few days there have been many somewhat overblown ideas circulating about the dangers of Raac: that it is a fundamentally flawed material, that it only lasts a few decades, or that it is something like “an Aero bar” in terms of strength. These are worth pushing back on. But, at the same time, there are real dangers posed by buildings with poorly constructed, degraded or poorly maintained Raac. And, if anything, the discussion so far has often underplayed the scale of Raac-containing buildings around the UK.

I predict that we will be hearing about Raac for quite a long time. While the current discussion is focused on schools and hospitals, Raac has been used widely across Britain. There will be Raac in some universities, in cold-war era military buildings – including many old and possibly disused structures, for instance, on the remote Scottish coastline – and in local government, central government, police and ministry of justice buildings.

Add to this that Raac wasn’t solely used in the public sector, then that there are many privately held buildings – for instance, the 60s and 70s-era, flat-roofed industrial structures that one sees in many business parks – that could possibly contain the material. These will be especially hard to catalogue as record-keeping and indeed establishing ownership of privately owned structures is more difficult than it is for publicly owned buildings such as schools.

And while the failure to catalogue and repair potentially dangerous Raac in schools has been held up as evidence of a particularly British kind of failure, the UKcould now be considered a world leader in understanding the long-term implications of Raac as a structural material. Our group at Loughborough and the Institute of Structural Engineers (IStructE) Raac Study Group are among the few researching and publishing about the long-term problems with the material. It is likely that other countries are watching what is happening in the UK at the moment, and they will begin their own investigations – and perhaps experience a storm of news coverage about Raac – fairly soon.

But while the scale of construction using Raac in the UK and elsewhere hasn’t quite sunk in yet, the actual dangers of the material have sometimes been overstated. There is nothing in our research that has suggested Raac immediately fails after 30 years, or that it is a uniquely dangerous material. TV clips of Raac pieces being snapped in half are unhelpful. No material or building lasts for ever, and much depends on how it has been manufactured, installed and maintained, and how it is used. Our research suggests that properly maintained Raac can easily last 50 years, and should be able to carry on for several decades after that.

However, Raac that has been improperly installed, suffered damage or hasn’t been waterproofed adequately could pose a risk. There is often Raac in flat roofs, and it may sustain water damage when waterproofing hasn’t been maintained; this is common when funding is tight and whoever manages the building responds only when leaks spring up, rather than preventing them in the first place.

The urgent task now is to find out where Raac is in buildings and assess the state it is in, and then address any potentially dangerous sites. This is not an asbestos situation, but rather one where we will probably find many buildings where the material is used safely, and also some that must be fixed by replacement or structural strengthening.

This isn’t an impossible goal. The NHS has led the UK – and probably the world – in addressing the issue. Because the organisation was extremely concerned about the danger of a hospital or ward having to close, over the past few years it has worked tirelessly with experts and industry to determine which hospital buildings contained Raac, and have replaced or strengthened it where appropriate. The NHS has some advantages here, as hospitals are large buildings with 24/7 maintenance staff who know the structure inside and out.

The DfE ran up against this problem when it asked schools to self-report on Raac. Communicating with some 22,000 schools is tough, and asking a small school to find a trusted engineer to do an evaluation is a big ask. There needs to be a more coordinated effort as we begin to address this issue more widely. Especially as there will be a capacity question: there are limited numbers of surveyors, engineers and builders with the right experience to work on Raac.

But there is also an opportunity here. Raac was built into our environment, and we will be living with it for a long time. But if we can respond to this immediate crisis by dealing with Raac across the country, pioneering the expertise to get it done quickly, safely and effectively, we will become a model the rest of the world can learn from.