On the one side Big Timber is saying think again; one the other side is Big Concrete, urging the government to hold firm.
The re-think on what building materials are safe to use in high-rise buildings was triggered by the 2017 Grenfell Tower fire, where the cladding system – erroneously but widely considered compliant with building regulations – acted as a lethal accelerant.
As part of a subsequent wide-ranging review of building safety, in January 2020 the Ministry of Housing, Communities & Local Government published Review of the ban on the use of combustible materials in and on the external walls of buildings.
This consultation sought views on the ban of the use of combustible materials in and on external walls of buildings, including building types covered, height threshold, list of exemptions, attachments such as blinds, shutters and awnings, and a proposal to specifically ban the use of metal composite panels in and on the external walls of all buildings.
The consultation process was originally due to close last month but was extended by six weeks to 25th May 2020 because of the coronavirus outbreak.
The government proposes that the height of timber-based buildings used for housing and accommodation would be limited to 11 metres. In higher buildings, timber would be allowed in floors but not for external walls.
The timber industry has come out firmly against this and warned that restricting the use of timber will compromise the drive for next zero carbon construction.
The Timber Trade Federation says: “There will be serious consequences felt right across the construction industry if the government extends this ban, including negative impacts on: modular construction, by severely limiting the palette of materials available to support MMC; sustainability, as timber has the lowest embodied carbon of any construction material; housing targets, because this ban will increase the cost and time of construction projects.”
It says: “The best way to improve this legislation would be to focus any extension of a ban on combustible materials down to 11 metres on the external cladding, not the structural wall itself. Making such a change to the ban would also bring us into line with regulations in Scotland, which banned combustible cladding above 11 metres, but does not include the structural wall in the scope of the ban.
“One of the concerns which emerged from the Grenfell Tower fire was how quickly flames were able to spread across the surface of the building. This occurred due to the external combustible cladding and was not related to the structural walls. There is no evidence that structural walls pose the same fire risk as the external cladding, and so there is no justification for treating the two in the same way.”
However, UK Concrete, part of the Mineral Products Association, has told the government that the combustibles ban should come with no exemptions and no further testing.
Chris Leese, director of MPA UK Concrete, says: “While legislation continues to allow for potentially combustible materials for buildings where many people – including the vulnerable – sleep, any U-turn would mean that the UK is continuing to knowingly build more and unnecessary risk into the heart of our built environment.
“Last minute calls for government to fund costly research into the fire performance of some materials would simply leave fire performance to chance. Public safety is critical, and if further testing is required of materials like cross laminated timber there is already too much doubt about its ability to protect people.”
In its response to government MPA UK Concrete says that a ban on combustibles would not restrict designers from making sustainable material choices.
Chris Leese adds: “A ban on all combustible materials in construction would not jeopardise the government’s ability to meet its commitment to reach net zero carbon by 2050. It is vital therefore that the debate on fire protection is informed by the facts, and not misperceptions about the carbon performance of concrete.
“Concrete and concrete products can be part of a net zero society, and are being used to construct buildings that have a low environmental impact due to better whole life performance through superior energy efficiency and reduced maintenance requirements over their long lifetimes. The concrete and cement industry has demonstrated that it can decarbonise and it will continue to support government to meet the net zero target.”