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NEWS ANALYSIS

Combustible cladding ‘ban’ – what do we really know?

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Grenfell survivors say the government’s ban is a crucial first step towards reforming the industry, but it has also been criticised as inadequate and short on detail. Ella Jessel investigates

A fire chief recently described his shock on realising Grenfell Tower’s concrete core was not ‘protecting itself’ from the blaze.

‘The cladding was continuing to burn and the fire was travelling and burning in all directions; horizontally, vertically upwards and downwards and so wrapping itself around the building,’ he told the ongoing public inquiry.

Now – 15 months after the tragedy – the government has announced a ‘ban’ on the deadly combustible panels widely blamed for helping spread the fire that claimed the lives of 72 people.

The move has been long in the making. Following the Hackitt Review, which recommended changes to testing but no outright ban, ministers announced in June that they nevertheless intended to prohibit combustibles.

But the way the policy was unveiled – sandwiched in the middle of housing secretary James Brokenshire’s speech to the Conservative Party conference in Birmingham and accompanied with four lines of ambiguously worded text – has been greeted with incredulity. 

‘Ridiculously frustrating’ was the response from one regulations expert.

Critics claim the initiative fails to deliver the ‘outright ban’ on combustibles that campaigners have fought for

The ban – expected to come into force later this autumn – has been cautiously welcomed by Grenfell United, a group representing survivors and bereaved families, which described it as the ‘first signal we are being listened to’.

However, in a recent opinion column for Inside Housing, survivor Ahmed Elgwahry, who lost his mother and sister in the fire, made clear the ban was just the ‘start of the conversation not the end’ and that ‘root and branch’ changes were required in how the industry approaches fire safety. 

‘Inadequate’ response

The government says it plans to change the Building Regulations to ban materials that do not achieve a classification of A1 or A2. These categories include metal, stone and glass, which seldom contribute to fires, and plasterboard, which makes no significant contribution.

The policy – which will bring England and Wales into line with Scotland and other EU countries – will apply to the ‘external walls’ of all new schools, hospitals, care homes, student accommodation and residential blocks rising over 18m. It is understood the ban will not be retrospective. 

Grenfellchirlajon

Grenfellchirlajon

But critics claim this fails to deliver the ‘outright ban’ on combustibles that campaigners have fought for. The RIBA described the ban as ‘not an adequate response to the tragic loss of life’. 

The London Fire Brigade Union’s (LBU) general secretary Matt Wrack says the ‘partial ban’ is designed for ‘political convenience, not for thoroughgoing change’, and the measure should apply to all buildings, not just new-builds.  

Wrack also argues that the policy will still allow A2 materials – classified as ‘limited combustibility’ – to be fitted to buildings. 

‘The FBU called for a universal ban on these flammable materials,’ he says.

In its submission to the consultation, the London Fire Brigade raised concerns over A2-rated materials. 

This is echoed by the RIBA’s Adrian Dobson, who points out that this will not place any limits on toxic smoke production, which ‘very likely contributed to the disproportionately high loss of life at the Grenfell Tower disaster’. 

Meanwhile, National Education Union assistant general secretary Andrew Morris says it is ‘incomprehensible’ that the ban will not cover all schools. 

Unanswered questions

In addition to concerns over the extent of the ban, the scant detail in the announcement has left huge questions hanging over what the policy will really mean for the industry.

Fire-safety and Building Regulations expert Geoff Wilkinson says the lack of clarity in the policy is ‘unacceptable’, with no detail on what will happen to existing buildings or projects currently under construction not to mention what – in the government’s view – constitutes an ‘external wall’.   

He warns: ‘We’re in danger of rushing through on a political whim something that could have massive consequences one way or another.’

The announcement, says Wilkinson, does not make clear whether primary legislation will be changed or official fire safety guidance altered. The latter option, he adds, will not constitute a ban. ‘The only way you could make it a ban is to actually ban it – like asbestos.

‘They are not [currently] banning combustible cladding and insulation,’ he says. ‘They are restricting its use and preventing its use on certain types of building over a certain height.’ 

Testing

When the ban does come into force, one of the big changes will be how architects achieve compliance, says PRP partner Andrew Mellor, head of the practice’s development consultancy which is working with the government on research into the Building Regulations.

The recent housing department circular has effectively stopped the use of written assessments or ‘desktop studies’, Mellor believes, while the combustibles ban also implies an end to the use of the performance-based route for testing cladding systems.

This route involves a large-scale test known as BS8414, which uses a demonstration wall representing a high-rise building to measure fire spread. 

However, following the ban, he thinks these will be obsolete and the only valid way of testing will be the ‘linear route’. This requires that each individual material is classified as either A1 or A2 – all other materials will be prohibited regardless of how they might perform in a demonstration test. 

‘Architects will quickly need certainty of the route to compliance from government but also across building control bodies, because the industry is currently experiencing very mixed approaches from inspectors,’ says Mellor. 

Cross-laminated timber

Anthony Thistleton, of cross-laminated timber (CLT) specialist practice Waugh Thistleton, warned earlier this year that the government’s proposal to ban combustibles in the ‘complete wall assembly’, including the inner leaf, insulation and the façade, could ‘spell the end’ of CLT construction in the UK.

Timber industry bodies and CLT specialists have been lobbying the government over the proposals, arguing that the construction method, when correctly installed and protected, does not present any additional fire risks. 

Dalston lane daniel shearing crop

Dalston lane daniel shearing crop

Source: Daniel Shearing

Waugh Thistleton’s Dalston Works is one of the world’s largest CLT structures

But the industry has interpreted the government’s latest iteration of the ban – as applying to ‘external walls’ – in a positive light. 

Commenting on Brokenshire’s statement, Thistleton says: ‘We understand that the proposed legislation will not impact the use of cross-laminated timber in construction.’

Timber Trades Forum managing director David Hopkins agrees, saying he thinks the government’s ban relates to the ‘surface’ of exterior walls rather than a building’s structure.

He does, however, raise concerns that under the proposals, timber cladding could be banned across the height of a high-rise building, meaning it could potentially no longer be used on street-level shop fronts in mixed-use schemes. Hopkins adds that, after Grenfell, the timber industry has been suffering from the incorrect perception that wood is less safe than other materials. ‘I don’t see this [ban] as referring to CLT,’ he says, ‘but the worry for us is the rhetoric, rather than the reality. They [timber products] start to get engineered out in clients’ minds.’ 

Post-Grenfell, many clients became more cautious, designing out risks rather than waiting for changes to regulations

Client caution

Post-Grenfell, architects have described how many clients immediately became more cautious over fire safety, designing out risks rather than waiting for consultation results or changes to regulations.

Luke Tozer of Pitman Tozer Architects tells how, on one project with a brick envelope below 18m, the client decided to install mineral-wool insulation and sprinklers during construction, to ‘reassure themselves and future residents’ they had done everything possible to ensure resident safety. 

‘The increased political awareness has also meant greater scrutiny at planning committees when proposing tall buildings, and the need to publicly explain future residents’ safety in a post-Grenfell era.’

Child Graddon Lewis associate director Greg Jones says his practice has a ‘standard policy’ against using any combustible materials not classified A1 or A2 on its schemes, and he suspects this is common across the profession.

He points out that clients are also looking ahead to issues with insurers. ‘We are already seeing this being taken hold of by clients who are pre-empting potential issues with future mortgage or insurance requirements by changing specifications, even on lower rise buildings, despite already achieving compliance with existing and emerging regulations,’ he says. 

Design implications

Beyond new testing routes and increasingly cautious clients, the ban on combustible materials will also have implications for design, including the need to find new products for façades that might be outlawed under the ban. 

Tozer says all his practice’s designs are now using deeper external wall build-ups from the outset, typically ‘550mm-600mm,  to allow for the thicker insulation and full brick or stone.’ He says: ‘As we had not used ACM [the cladding type used at Grenfell] or similar materials and have been enjoying an extended love affair with brick, the impact to us has mostly been in the insulation build-up and how that is integrated into the construction.’

The industry’s lack of clear guidance on fire safety is one of the reasons often given for why Grenfell Tower and 470 other high-rise buildings in the UK were fitted with cladding panels that failed combustibility tests.

The government’s consultation on banning these materials set out with the express aim of leaving the industry in ‘no doubt’ about which materials can be used on high-rise buildings.  

Yet in the ban’s current form, confusion still reigns. For the public though, the confirmation that the government will bring in new regulation is a welcome first step towards reform. 

‘We cannot continue to allow an industry that has shown itself to put people’s safety secondary to profits, to carry on regulating itself,’ wrote Grenfell United’s Elgwahry.

For architects, Tozer says, it is an opportunity to remind the profession that fire safety should be integral to design. ‘Design, as we all know, is not just how the building looks, but how it performs and the complex relationship between those two. 

‘As a profession we have a chance to lead in the necessary culture change, to produce safe buildings that the public, our ultimate clients, deserve.’

Key questions

  • Live projects The ban is not expected to be retrospective, but one of the biggest unanswered questions is whether it will be applied to high-rises currently under construction. 
  • Buildings’ scope The policy will apply to all residential buildings taller than 18m, as well as new schools, hospitals, care homes and student accommodation rising over that height. But some have questioned why office blocks and hotels are not included. (The London Fire Brigade recommended banning combustibles on any building of any height.)
  • External wall The policy applies to the ‘external wall’ of buildings, but for architects working with cross laminated timber (CLT), whether this includes the complete wall assembly, including the inner leaf, insulation and the façade, will be crucial. 
  • Regs change Questions remain over whether the policy change will be brought in through an alteration to the government’s official fire safety guidance (Approved Document B), or a change to the mandatory Building Regulations. The government’s consultation indicated a preference for the latter. 
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