How High is the Cladding Risk?

How high is the risk of combustible materials on the exterior buildings, like cladding? In December 2018 the Government amended the Building Regulations to restrict the use of combustible materials in and on external walls and specified attachments like balconies.

The Government committed to review the effectiveness of the ban after 1 year so in Jan 2020 they released a new consultation on proposed changes to the Regulations. The new consultation looks at the current scope of the ban, the list of exemptions, and proposals to include additional attachments to external walls in the ban.

The consultation firstly proposes a ban on the use of metal composite panels in and on the external walls of all types of new buildings, those undergoing a material change of use or building work.

Following several high-profile fires there have been calls for the ban to be extended.  Currently the ban only applies to buildings above 18M containing one or more dwellings but there are calls to reduce this to 11M. There is currently no robust evidence that there is a significant reduction in risk with buildings between these heights. It is however considered that below 11m traditional external fire-fighting techniques can minimise the risk. 11M is currently used in Scotland as the threshold for more stringent provisions on external wall construction, although not an outright ban.

Whilst the ban does not apply to existing buildings where no work is being carried out, future legislation will require a case by case risk-assessment and buildings below 11M may need combustible material removed.

The final proposal to consider relates to the use of laminated glass in balconies. There is currently no laminated glass available which can achieve the appropriate classification (i.e. class A1 or A2-s1, d0) because of the interlayer used to bind the two glass layers together. The use of monolithic toughened glass in balconies does not comply either as it creates other safety issues when it breaks.

As a result, it is effectively impossible to design balconies using glass that can achieve all the required safety measures and fire classification. The ban will remain in place, but the Government intend to commission research on the use of laminated glass to better understand its contribution to fire spread and overall risk before considering whether to exempt laminated glass in balconies. Therefore, it is likely to be at least another year before this problem will be resolved.

Credit: Geoff Wilkinson – Managing Director, Wilkinson Construction Consultants.

This article was originally featured in Insight Magazine, subscribe for your free copy every quarter here.

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