It’s now more than three and a half years since the tragic events at Grenfell Tower, but the issue of building safety and, in particular, cladding safety is still making headlines. Recent reports about the number of buildings where occupiers have to pay huge sums for fire watch patrols while they continue to wait for the cladding on their building to be replaced indicate the ongoing impact of historic specification choices.
Grenfell was a catalyst for change. It is now two years since legislation was passed making it mandatory for cladding used on high-rise residential buildings (HRRBs) of 18m and above to be certified to A1 or A2-S1-d0 to BS EN 13501-1. This means that homebuyers and investors purchasing a recently-completed apartment or a development currently on site can rest assured their cladding is non-combustible. The question remains, however, does compliance with legislation mirror cladding safety specification best practice?
The Hackitt inquiry and the subsequent legislative process have certainly done much to raise awareness of safety issues in the cladding specification process. There has been increased vigilance throughout the delivery chain – from client and architect through to main contractor and cladding installation specialist – as a result. However, the safety focus for many involved in the specification and procurement of cladding remains firmly centred on compliance rather than a true consideration of all the safety implications of their product choices throughout the building’s service life.
Focus on maximum fire safety
One of the consequences of the continuing investigations into the Grenfell disaster is an anticipation of further legislative change. Developers want to ensure that their building will be compliant following completion, and fire safety has become an essential marketing message for residential projects, along with a duty of care to future residents. Architects and other consultants are also keen to future-proof the specification by ensuring optimum fire safety certification levels are embedded in product choices. For many projects, this has resulted in a performance requirement of A1 certification – even though A2-S1-d0-certified materials also currently comply with requirements for residential buildings above 18m.
This belt and braces culture when it comes to fire safety is good news for future residents and the building’s longevity. However, it is starting to have an unintended safety consequence, which could result in increased safety risks for the building, expensive remediation and even liability for accidents.
The vital role of mesh
The side effect of the widespread insistence on the use of A1-certified cladding materials tends to omit the anti-fragmentation mesh, which is sometimes necessary for pre-fabricated cladding panels, to maintain A1 classification. Most mesh and mesh bonding adhesives used in cladding panel fabrication do not meet A1 or A2-S1-d0 classification requirements, so, once this has been adhered to the rear of the panel, the panel can no longer be classified as A1. The safety emphasis on non-combustibility is such that an A1 certification is prioritised above the inclusion of anti-fragmentation mesh.
However, anti-fragmentation mesh has a vital role to play in the safety of any brittle cladding material, so most responsible specialist stone and ceramic granite suppliers recommend it, particularly for installations at a high level. In the unlikely event of a high-level impact, the mesh prevents large fragments of the cladding panel from falling from the facade. Without it, falling pieces of cladding material have the potential to land on pedestrians or vehicles below, and the higher the location of the panel, the greater the velocity of the fragment when falling.
Combining fire and fragmentation safety
For these reasons, Shackerley has developed an A1-certified bonded mesh, enabling A1 materials within the Shackerley SureClad range (ceramic granite, natural stone and terracotta) to provide an A1-certified system without compromising on any aspect of safety. As part of a rigorous approach to building safety, for both occupiers and the general public, Shackerley always advises the inclusion of anti-fragmentation for all brittle cladding materials. This is bonded to the cladding material at our ISO 9001 factories in Lancashire using specially-developed mesh and bonding methodology. Where the specification is for an A1-certified panel, the A1 mesh should be used. Under no circumstances should any brittle cladding material be installed at a high level with no anti-fragmentation mesh at all.
The Grenfell disaster consequences have led to significantly enhanced safety awareness for a whole range of building elements, not just the building envelope materials implicated in the rapid spread of fire. Attention is now being focused on compartmentation and the combustibility of other building materials too. Hopefully, this focus will lead to much less risk of catastrophic fires in the future, but we must not let it cloud our vigilance in other areas of safety. The goal for all involved in the cladding sector should be for those awful events to be a catalyst for innovation that makes our built environment safer and more robust across all aspects of hazard and risk.