The government has commissioned an urgent review of building regulations and more than 200 tower blocks around the UK need to have some or all of their cladding replaced.
The Building Research Establishment has conducted large scale tests in its Burn Hall on seven different combinations of aluminium composite material (ACM) cladding and insulation types. The results of these tests (see below) will inform what replacement materials are appropriate for use.
Inspections carried out since the fire have also highlighted other safety issues related to building design.
For example, as communities secretary Sajid Javid told the House of Commons yesterday, structural engineers studying Southwark’s Ledbury Estate have found that strengthening work may be needed on blocks constructed using the concrete panel system that failed at Ronan Point in 1968.
“They also raised concerns about cracks that appeared cosmetic but could compromise fire-safety compartmentation,” Mr Javid said. “We have been in contact with Southwark Council and the engineers to discuss these issues, and have engaged the Standing Committee on Structural Safety to advise on their implications.”
He added: “Meanwhile, all local authorities that own similar buildings have been advised to review their designs and to check whether any strengthening work was properly carried out.”
Post-Grenfell investigations have thrown up other hidden problems too, Mr Javid said. “Separately, the British Board of Agrément has told us that, based on their investigations following incidents in Glasgow, some cladding systems may be designed and installed in such a way that they could fail in strong winds. We’re not aware of any injuries caused by this kind of failure. However, we are taking advice from the independent expert panel and have written to building control bodies to draw their attention to the issues that have been raised.”
The wider issues of competence and certification will feed into Dame Judith Hackitt’s review of building safety, he said, while the Industry Response Group is expected to help coordinate moves to improve building safety.
The full legal ramifications for the many companies involved in installing, specifying, selling and certifying cladding and insulation materials now revealed to be not compliant with the regulations will likely only become apparent once the public inquiry has completed and reported.
However, many companies are already experiencing an impact, as a result of the shift in priorities among landlords.
Mears, for example, does most of its work for local authorities and housing associations. It has warned shareholders that its 2017 revenues will be £30m below target as a result of the Grenfell Tower fire. It said that “clients' attentions have naturally been diverted towards ensuring their housing portfolios are safe and fully compliant”. As a result, Mears expects delays in planned works orders.
Mears chief executive David Miles said last month: “Whilst the likely revenue shortfall for the full year is frustrating, it is entirely understandable in the circumstances and the group will be working closely with its partners and clients at this time to address their immediate priorities.”
BRE fire test results
The Building Research Establishment has conducted BS8414 flammability tests on six systems incorporating each of the three common types of aluminium composite material (ACM) panels, with core filler materials of unmodified polyethylene, fire retardant polyethylene, and non-combustible mineral. The two insulation materials used in the testing are rigid polyisocyanurate (PIR) foam or non-combustible mineral wool. The seventh test focused on phenolic foam insulation.
Three combinations are deemed to have passed the BRE’s fire tests, indicating that they could be compliant with building regulations guidance BR 135 when installed and maintained properly.
- ACM panels with a fire resistant polyethylene filler (category 2 in screening tests) and stone wool insulation;
- ACM panels with a limited combustibility filler (category 1) with stone wool insulation;
- ACM panels with a limited combustibility filler (category 1) and polyisocyanurate (PIR) foam insulation.
Combinations that failed and were shown to be not compliant with BR 135 were:
- ACM panels with unmodified polyethylene filler (category 3) with PIR foam insulation. There are 82 buildings in England over 18 metres high that are known to have this combination.
- ACM panels with unmodified polyethylene filler (category 3) with stone wool insulation. There are 111 tall buildings with this in England.
- ACM panels with a fire retardant polyethylene filler (category 2) with PIR foam insulation. There are 13 tall buildings with this in England.
- ACM panels with a fire retardant polyethylene filler (category 2) with phenolic foam insulation. There are 22 tall buildings with this in England.
There are a total of 228 tall buildings in England over 18 metres high that are known to have combinations that failed the tests, including 165 social housing tower blocks and 59 privately-owned student housing towers.
Social landlords and local authorities that own affected buildings have been given detailed advice drawn up by the government’s independent expert advisory panel.
The Department for Communities & Local Government has also been holding weekly update calls with local authorities, housing associations and other building owner groups.
Yesterday it published further advice, bringing together all the results and the views of the expert panel on the implications for building owners. [Click here to download it as a pdf.]
“We will shortly be meeting with local authorities and housing associations to discuss further steps,” secretary of state Sajid Javid said. “This will include the process by which we will ensure that remedial work is carried out. We have made the BRE tests available to all private residential building owners too.”
Camden Council has this week begun work to remove the cladding from its Chalcots estate. The cladding system is being be taken off the two bottom floors at Blashford and Burnham blocks initially. A specialist team will then assess the work and set out a plan to remove the rest of the cladding from the end of September.
Camden Council leader Georgia Gould said: “Residents have made it clear to me that they don’t want this material on their building and we’re determined to move fast and take it off. It is important that we know what options are open to us once cladding is removed so, to move things along quickly, we have appointed our own specialist design team to come up with the right solution for the Chalcots.”