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According to experts, tens of thousands of government and privately owned buildings should undergo safety inspections due to disintegrating RAAC concrete.
The group that alerted the government to the dangers posed by the concrete stated that regular safety inspections would be required.
Prof. Chris Goodier stated that the majority of afflicted structures were probably not hazardous, but that they should be inspected anyway.
“We’ve discovered that a portion of our building stock is not as good as we previously believed,” he said.
“It’s a small percentage, but we have millions of buildings – even 1% of 10 million buildings is 100,000,” he said.
Prof Goodier said that as well as government buildings such as hospitals, courts houses, and prisons, an unknown number of private sector offices and warehouses were also potentially affected because they contained the concrete, also known as reinforced autoclaved aerated concrete (RAAC)..
His group is advising the government to dispatch surveyors to evaluate the affected structures, the majority of which the researchers expect to have no hazardous flaws. However, they will require periodic inspections.
A limited number of buildings may require reinforcements or closures, and a few may need to be rebuilt.
Prof. Sergio Cavalaro of the Loughborough team says that in the long run, a new approach involving regular inspections and administration of potentially tens of thousands of buildings will be required.
“Buildings that were not previously inspected must now be inspected. We must increase the frequency of these examinations. However, this will be difficult because so many buildings require inspections. Therefore, we may lack the qualified personnel to complete the task punctually,” he said.
The researchers refer to this material as “living with RAAC” and believe it should be handled similarly to the asbestos crisis of the 1980s.
According to Prof. Goodier, it will not be obvious how much RAAC is involved until the assessments are conducted.
“Forty very large hospitals have 10,000 RAAC planks in their ceilings, and some have spent £10 million to maintain them. There are 22,000 schools and they discovered 150 with RAAC, but their sizes differ greatly and some are quite small.
”However, the public sector is the easiest part because the government has control and is aware of its location. Prof. Goodier stated that the private sector consists primarily of 1960s and 1970s offices, factories, and warehouses. Also potentially some housing where the owner is unknown.
The research conducted by the Loughborough team demonstrated that the potential hazards of RAAC were greater than previously believed. Although the material has been used for decades, very little research has been conducted on its aging.
The team began investigating the issue on behalf of the NHS two years ago.
They identified three major factors that risk assessors had not adequately considered.
RAAC absorbs water like a sponge and increases the building’s load when subjected to precipitation.
Stress experiments revealed that the material is 25% weaker when wet.
Microscopy analysis revealed that cracks can appear around the steel rods that pass through the RAAC.
According to the researchers, a lack of appropriate maintenance makes all of this more likely.
Worse yet, these issues are not readily evident until the material breaks.
“Collapse after something appears to be about to collapse is one thing; collapse without warning is cause for concern,” explains Professor Goodier.
A government spokesperson stated that the decision was based on expert advice. “That professional advice from experts on RAAC has evolved, from advice in the 1990s that RAAC did not pose a safety hazard to more recent advice on identifying and assessing structural adequacy,” the spokesperson explained.
