The Grenfell Tower tragedy is one of the most tragic incidents in recent UK history. The fire started in the tower block by a malfunctioning fridge-freezer unit on the fourth floor. The fire spread rapidly up the building’s exterior, soon engulfing the building in fire and smoke. The fire burned for 60 hours before it was extinguished, and cost the lives of over 70, and removing over 200 people from their homes.
The stack effect is the movement of air into and out of buildings, resulting in air buoyancy. Air buoyancy is impacted by the temperature differences on the inside and outside of the building and the height of the building. It is thought that the fire at Grenfell was exacerbated by the stack effect, explaining why the fire spread so quickly. There was a cavity between the outer aluminium cladding and the inner insulation which formed a chimney, drawing the fire upwards through the high rise.
Due to the safety issues with the cladding and insulation, many high-rise tower blocks were found to be unsafe. Since Grenfell, government and regulatory bodies have attempted to regulate insulation materials and cladding, especially in high rises. There is a lack of steer or direction for which cladding and insulation materials are suitable for use in which type of development. Perhaps, the largest issue resides in ‘whose responsibility is it to fix the cladding?’ Is it the architect? The building owners? The construction companies? The owner of the properties?
Many companies in the UK will be looking to retrofit cladding materials in their high rises in order to meet regulatory requirements. That means that these companies will be looking to and experimenting with different cladding and insulation materials to properly insulate the building, but also mitigate the stack effect and thereby mitigate fire spread in future developments.
An additional area of complexity comes in understanding how cladding and insulation materials combust when paired with other materials, as well as how these materials interface with waterproofing measures and acoustic materials in the building’s fabric. Further testing will surround mitigating horizontal fire spread, as well as vertical fire spread – which can be very different in different applications and building types. Companies will be wanting to create cladding and insulation detailing that is safe, performs well in terms of thermal and acoustic performance, but is also as thin as possible to maximise the sellable and liveable areas of a building.
Further complexity arises when attempting to secure cladding to buildings. Companies will be looking at different fixing materials to secure cladding to the insulation, without creating large air gaps. In addition, fire-safe cladding can be extremely heavy, which can greatly impact building stability and sway when used in high-rise buildings. This problem is further exacerbated when looking at how materials perform in fire situations – steel can warp, and cause the building to become unstable. Companies that are undertaking this work can be eligible for R&D tax credits when attempting to retrofit, reclad and experiment with materials to improve the safety of these high rises.
This has come off the back of £3.5bn government funding to remove the unsafe cladding on high-rise buildings over 18m high. This was on top of £1.6bn funding announced last year. However, the funding only applies to buildings over 18m high. Campaigners for safer buildings deem this ‘too little, too late’ and don’t account for lower blocks that are 17m high.
If you have any further questions about this topic please do get in touch with us.
Georgina Keys, Senior Specialist Tax Consultant, Catax