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Cladding: How Grenfell is changing the market forever

grenfell cladding exterior

The cladding sector has faced more scrutiny than almost any other part of the industry since the tragic events at Grenfell. Lucy Alderson analyses the biggest concerns, the impact of uncertainty and how companies are now responding.

At 12.54am on 14 June 2017, London’s fire brigade was called out to a 24-storey residential block in west London.

When they arrived at Grenfell Tower just after 1am, fire had already taken hold of the building. The tower continued to burn over the next 24 hours before the last of the flames were finally put out.

The speed at which the fire spread though the tower immediately raised questions over whether the ACM cladding – which was fitted onto the building’s exterior as part of a refurbishment completed by Rydon in 2016 – acted as fuel for the fire.

Evidence now indicates it was.

Barbara Lane, a chartered fire engineer and leader of fire safety engineering at Arup, gave evidence to the Grenfell Tower Inquiry on the first day of expert witness statements this month. She concluded that the rainscreen cladding system was not compliant with current Building Regulations.

Dr Lane added that the cladding material, Reynobond 55PE, contributed to the “most rapid of the observed external fire spread”. The maker of Reynobond, Arconic, says the panels were “at most, a contributing feature” to the fire.

The families of those who died are seeking answers on how Grenfell Tower could have been signed off and handed back to hundreds of families, given how quickly the fire eventually spread.

Among the issues are current Building Regulations themselves, which many industry experts and lawyers claim are not fit for purpose and require major clarification. 

The system of combustibility tests for building materials has also come in for scrutiny, raising additional concerns over just how confident construction firms can be in specifying these products.

These factors mean that serious questions over cladding remain unanswered, leaving the industry confused and nervous about which materials are safe to use – even if they have passed fire safety tests.

With the market gripped by this uncertainty, how do contractors tackle the cladding crisis and ensure another tragedy like Grenfell never happens again?

Regulation disagreements

Under current Building Regulations, Approved Document B (the technical guidance for Building Regulations) states that buildings over 18 m should have insulation that is of limited combustibility (under section 12.5 detailing guidance for external wall construction).

However, this wording is different from the guidance published by the British Standard Institute.

In the BSI’s document BS9991, section 18.2 outlines guidance around external fire spread over external faces of buildings. It states that not only should buildings over 18 m have insulation of limited combustibility (as per Approved Document B), but cladding materials should also be of limited combustibility.

“Grenfell doesn’t match the standard square face that is mocked up on tests because it was angled. It is simply not possible to have tested accurately the way in which the cladding and insulation was used on Grenfell”

Geoff Wilkinson, Wilkinson Construction Consultants

Furthermore, tension arises between how to compare and correspond British Standards and European codes together. The two standards use different grading systems to class the fire performance of materials, resulting in further confusion for the industry as it is asked to justify its choices about materials and whether they are compliant.

As a result, Building Regulations surrounding cladding are in “a mess”, according to Barry Hembling partner at law firm Fladgate. “The issue is: how have we had so many buildings being signed off as compliant with Building Regulations?” he asks. “This can only be because the Building Regulations are inconsistent [with regards to] understanding what the appropriate standard that ought to be met actually is.”

Material labelling concerns

Grenfell has damaged confidence in the fire safety labelling of building materials, Mr Hembling suggests.

Looking at the specification of the insulation used on Grenfell (Celotex RS5000) prior to the fire, the product’s labels state that Celotex has class 0 fire performance.

The Building Regulations state buildings over 18 m should have insulation that is of limited combustibility – and limited combustibility is graded as Class 0 in Approved Document B.

“The question arises: how do we have a product on one hand that says it is compliant with relevant standards, whereas on the other hand we now know that product wasn’t compliant?” Mr Hembling asks. “This is a really important point we need to have clarified which has not yet been clarified.”

He adds that this raises another important issue. “It identifies the lack of certainty about the labelling of construction materials and the extent to which the construction industry can generally have confidence in those labels.”

CREDIT Metropolitan Police_Grenfell Tower fire London exterior

CREDIT Metropolitan Police_Grenfell Tower fire London exterior

Source: Metropolitan Police

This lack of confidence in product certification has been observed by Speedyclad commercial director Tony Blake.

Following Grenfell, Mr Blake says he noticed fire barriers (products installed around buildings to reduce the spread of smoke and fire) were being withdrawn or reclassified. “Manufacturers would make claims that their fire barriers met the standard, but they would only meet standards if they are tested in a specific way, as you could only use them in the way that they were specifically tested,” he says.

By this, Mr Blake means that, while some fire barriers may have passed the BRE test when combined specifically with certain building material products, they may have failed if combined with different products.

He suggests the “big conundrum” is the lack of confidence this creates in the labelling of building materials.

Doubts over fire safety tests

Concerns over the reliability of fire safety tests increased even further in April this year, following research conducted by the Fire Protection Association (FPA).

The FPA investigated the competency of laboratory tests currently used to check the fire safety of building materials. Fire and industry experts were concerned about whether the standards set by the British Standards Institute for these tests were fit for purpose.

Concerns surrounded whether the tests adequately reflected ‘real-world’ conditions, rather than simply the conditions in a laboratory setting.

The FPA’s ‘real-world’ tests led to larger areas of cladding being consumed more rapidly by fire, and produced temperatures that were significantly hotter than in BS tests. Indeed, one test the FPA cariied out involving burning plastic commonly found in home and office fires had to be stopped, as the heat of the fire threatened the safety of one of its labs.

“The market became very nervous; no one wanted to make any decisions and put any cladding on the walls for the first three to six months”

Ben Jayes, Vivalda

Wilkinson Construction Consultants managing director Geoff Wilkinson, who is a Building Regulations expert, says these BS8414 tests, which are carried out by the BRE, need to be reviewed in the wake of Grenfell.

He explains that these tests involve a particular combination of insulation, cladding and so forth, designed to mimic a wall of the building in question. The tests are conducted on an L-shaped piece of cladding, as though setting fire to a corner of the building. However, the geometry of Grenfell’s corners was different to this L-shape used in BRE tests.

“There can’t have been a test on the [actual] Grenfell layout, as this is different to the British Standard test layout,” Mr Wilkinson says. “Grenfell doesn’t match the standard square face that is mocked up on tests because it was angled. It is simply not possible to have tested accurately the way in which the cladding and insulation was used on Grenfell.

“That is one of the problems – you cannot replicate exactly every possible geometry or configuration that you may have on a building.”

Response in the cladding sector

The confusion and concern around cladding post-Grenfell has prompted some cladding specialists to take action.

Stanmore managing director Raj Manak argues that an appropriate response is to conduct fire safety tests on every single one of its facade jobs, with each test costing around £20,000.

His firm  – and others – have also been sending off their materials to private testing facilities in Dubai, as the BRE labs in the UK have a three-to-four-month waiting list because of increased demand for material combustibility tests.

Mr Manak says it is “difficult to say” how much these tests will affect the firm financially, but adds that the costs are being built into each facade tender. More broadly, the cost of buildings is rising due to a shift in the insulation materials now being used, he says.

Mr Manak identifies two main types of insulation materials used on buildings: phenolic insulation and mineral insulation. Before Grenfell, phenolic insulation was more widely used because it keeps heat within buildings more efficiently compared with its mineral insulation counterpart.

The thermal performance of buildings was a priority for the industry, Mr Manak says, because of pressure placed on contractors to minimise heat loss on buildings. “Government policy has been driven by having low carbon emissions,” he says. “That’s what caused the industry to use a lot more insulation which was CO2-friendly and stopped heat loss.”

grenfell s stock

grenfell s stock

Mineral insulation is now preferred over phenolic, as it performs better in fire safety tests. However, more of the material needs to be installed to avoid comprising thermal performance, meaning the thickness of external walls is increasing.

Mr Manak says contractors have to ensure the structural integrity of the building is not affected, which means more structural steel may be required. The result is that buildings are now “even more expensive to build” he says.

Fladgate’s Mr Hembling suggests companies using international testing rigs must ensure those tests are carried out to the standards that would apply in the UK. “Contractors will want to scrutinise the relevant test reports, as those who are testing products abroad need to provide detailed analysis about the basis on which those tests were carried out and the standards to which those tests satisfy,” he says. “Contractors will want to make sure they have an understanding of those issues.”

Another challenge facing cladding contractors is professional indemnity insurance, according to Mr Blake. Speedyclad has seen a significant increase in its future insurance premiums and a change in cover level. “We’re seeing massive hikes in insurance premiums, a reduction in cover and an increase in excess levels,” he says, estimating that many cladding contractors could be paying 10 times what they were before on insurance annually.

Suppliers and manufacturers: changing markets

In the immediate aftermath of the Grenfell fire, decisions around installing cladding on buildings ground to a halt, as Vivalda managing director Ben Jayes recalls.

“The market became very nervous; no one wanted to make any decisions and put any cladding on the walls for the first three to six months,” he says. “Naturally that affected our figures, sales desirability and demand for our product in the first instance. But equally, buildings still need to be built […] and at some stage, you need to make some fundamental decisions on putting some kind of material on the external skin of the facade.”

At that stage, Vivalda noticed a radical change in the types of products that were in demand – particularly non-combustible cladding (which are A1 and A2-rated products).

Products such as fibre cement, including glass-reinforced concrete, have picked up, Mr Jayes reports. “We’ve seen a shift in the products we sell,” he says. “Even social housing for instance – where clients have historically gone for lower-grade or lower-value materials – we’ve seen a shift in culture where they are going for high-end materials that are A1 and A2-rated.”

Fladgate partner Barry Hembling offers legal advice for construction companies.

Use specialists’ knowledge:  “Cladding contractors are relied on for their expertise and they often use that to judge which products are appropriate for a building.

“They need to be taking extra care over which products they select for use on buildings, and they need to be looking in much closer detail at the product manufacturer specification.

“These contractors would want to ask more questions about whether the product complies or not with the information that has now been available through the BRE, including historical data on cladding systems that satisfy Building Regulations standards.”

Non-ACM cladding:  “Following the fire, there has been concern about non-ACM panels with a near-identical construction.

“It’s important for contractors to apply the same rigid standards to all types of panel specifications. They [should] make sure they review the specification of non-ACM panel types and make clear these are issues that could extend more widely.”

Insurance:  “They will also be wanting to look at the terms of their insurance as well. To cover themselves, it may be that they want products liability insurance in place for products that they specify.

“[They should] ensure they are insured to provide comfort in the event that there might be any future claims against them, and equally be looking at insurance arrangements of the manufacturers that supply products to them.”

Mr Jayes says that one particular type of glass-reinforced concrete cladding made by German manufacturer Rieder is now being used on social housing blocks. To his knowledge, this product has never been used on social housing blocks prior to Grenfell and has only typically been used on high-end, luxury apartments.

Most noticeably, Mr Jayes says he has seen a marked change in attitudes towards responsibility and accountability of build quality. “From architects down to contractors and subcontractors, it’s very much a belt-and-braces approach and people are far more regimented towards responsibility, warranty and certification than ever before,” he says. “There is less demand and focus on the cost of materials and the focus has shifted dramatically towards the certification, fire [rating], integrity and longevity of the product.”

Manufacturers selling products that are not A1 and A2-rated have suffered as a consequence, according to Mr Jayes.

He says some of the smaller manufacturers are falling out of the market, as they lack the resources to conduct the regular expensive tests that have been in demand post-Grenfell. “That is arguably going to create a slightly elitist market,” he says.

Hackitt Report disappointment

Grenfell has put the industry’s accountability over building safety in the spotlight, and prompted calls for urgent reform.

It was against this backdrop that Dame Hackitt was appointed to review the current regulations and fire safety of buildings. However, despite calls for her to recommend an outright ban of combustible cladding, Dame Hackitt’s 156-page report did not mention it once.

Published last month, the report was criticised for stopping short of calling for a ban, with some also suggesting her recommendations could not produce the changes the industry required.

Speaking following the publication of the report, Dame Hackitt said: “If people think that simply banning cladding would fix it all, it won’t; it is a broken system and banning cladding on its own will not fix it.”

However, many across the industry have criticised this decision, believing it would have provided some clarity over what to do with combustible cladding – including Vivalda’s Mr Jayes.

“If people think that simply banning cladding would fix it all, it won’t; it is a broken system and banning cladding on its own will not fix it”

Dame Judith Hackitt on response to report

The company adopted a policy last year of selling only non-combustible materials to high-rise developments. Mr Jayes had hoped Ms Hackitt would recommend a ban on combustible materials on tall buildings. “I find the Hackitt report quite frustrating,” he says. “I think it was an opportunity missed to bring clarity to the construction market and the regulations we all work within. I don’t think that was achieved.”

The government announced a consultation on banning combustible cladding, just hours after the Hackitt report’s publication.

However, other aspects of her recommendations have also raised concerns, with Wilkinson Construction’s MD describing some of the suggestions as “really worrying”.

“One of the recommendations was to have a different standard for high-rise, high-risk buildings,” Mr Wilkinson says. “To come out with a conclusion that high-rise buildings are different from other buildings seems so wrong to me.”

The lack of fire safety traceability approval is not only a problem for social housing, he suggests. “Why couldn’t this be a problem on a three-storey school or a hospital? They’re all built in the same way.”

Mr Wilkinson believes the Hackitt report did not address the issues at hand. “I don’t think it is fit for purpose. Either it should have been looking at the technical aspects or it should have looking at the procedural aspects.

“However, what instead seems to have happened is that it has picked up on procedures relating specifically to tower block buildings. It doesn’t seem as though it answers any of the questions which we all know are issues in the construction industry.”

Until all the expert statements are heard and final conclusions reached in the Grenfell Tower Inquiry, uncertainty will persist over how to fix our testing and regulatory regimes.

One thing though is certain: Grenfell is having and will continue to have a permanent impact on the standards to which construction is held. 

Readers' comments (1)

  • In our opinion, it is unacceptable that many of the “desk top assessments” by Certification organisations of the cladding systems in use today still rely on small scale tests to predict the fire performance of “as-built” systems.

    We first raised our concerns in 1996 with the then Department of Transport and Industry (Dti) regarding reliance on small scale fire tests on cladding systems. Back then (22 years ago) we did not believe small scale British Standard BS 476 Part 6 and Part 7 tests to determine fire propagation and surface spread of flame classification respectively should be relied upon to predict the actual “live” performance in fire of “as-built” systems.

    We first carried out testing (part funded by Dti) in March 1997 and have been calling for full-scale fire testing of “as-built” cladding systems to be conducted on all types of cladding systems as standard practice ever since and would again reiterate, the lessons learned after the Irvine fire in 1999 all appear to have been ignored.

    Following the Irvine fire, the then House of Commons parliamentary committee investigated the potential for fire to occur in all cladding systems. The committee concluded:

    19………., we do not believe that it should take a serious fire in which many people are killed before all reasonable steps are taken towards minimising the risks.

    The evidence we have received strongly suggests that the small-scale tests which are currently used to determine the fire safety of external cladding systems are not fully effective in evaluating their performance in a ‘live’ fire situation.

    20. We believe that all external cladding systems should be required either to be entirely non-combustible, or to be proven through full-scale testing not to pose an unacceptable level of risk in terms of fire spread.

    We do not believe it should take another fire and even more fatalities to occur before a full investigation is carried out on all cladding systems on housing, including low, medium and high-rise Tower blocks.

    Reference: The Report and Proceedings of the Environment, Transport and Regional Affairs Committee, First Report, Potential Risk Of Fire Spread In Buildings Via External Cladding Systems, ordered by the House of Commons to be printed 14th December 1999 (HC109)

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