Zak World of Facades UK 2021
Patrick, was invited to be part of an industry expert Q & A panel at the recent Zak World of Facades in London 2021. These are the discussion points he raised during the session
Because of our previous experience in the re-cladding of buildings, we have found our services in demand over the last 18 months as the fire recladding of apartment buildings has accelerated.
This is of course in the wake of MHCLG guidance which requires flammable materials to be removed from the cladding of buildings with a floor over 18 m above ground level.
At PRA we have previous experience in the re-cladding of buildings, we have found our services in demand over the last 18 months as the fire recladding of apartment buildings has accelerated.
Challenge 1 - Finding Information on original construction
The first challenge that we face is with information. Our role as façade engineering consultants, is to identify any flammable materials that are present in the façade. This would be so much easier, firstly if there were any O and M manuals, and secondly if they contained contractor’s drawings and information on the cladding materials which were actually installed.
However sadly this is seldom the case, with the result that we need to knock holes in the walls caveman style to find out what’s there. We do also of course use borescope survey where we can, but what you can see is always limited. Hopefully in the future, with the adoption of “ The Golden Thread”, information will be retained electronically making any remediation much simpler (and maybe one of the other panel members can comment on this later). In my opinion, building owners must be required to keep comprehensive information on their façades and cladding in electronic format for future use.
At this point there is a fire engineering decision to be taken as to which materials can be left in place and those that need to be removed.
Challenge 2 - Designing a new cladding scheme for the building
Once it’s been decided what is going be removed, then we can set about writing a specification for the replacement façade, together with plans, elevations and detailed drawings which describe to the contractor exactly what work needs to be carried out.
Because the MHCLG prefer traditional contract rather than design and build (they regard design and build as part of the reason that buildings are now falling below acceptable standards) detail drawings are required on these recladding schemes (down to the nuts and bolts) rather than outline design. The correct selection of materials for the project is paramount, compliant with Building Regulations Approved Document B, revised 2019 edition.
The correct design and placement of cavity barriers is another essential element in the re-cladding as many of the buildings we have looked at either have badly installed cavity barriers, the wrong type of cavity barrier or no barrier at all! Very few of the buildings we have looked at, have cavity barriers installed around windows and doors. This needs to be corrected in the re-design.
The other major challenge in design is carefully managing the consultant's liability on these projects.There must be clear demarcation lines between the responsibilities of the different professions and between the professions and the contractor and these need to be understood by the client and their project manager.
Challenge 3 - Fulfilling all requirements within Building Regulations
Design of the re-cladding scheme needs to satisfy not just Approved Document B in relation to fire, but also Building Regulations requirements in terms of structural, thermal and condensation. We found this to be particularly difficult in the case of rendered walls, where the render is placed over insulation and condensation will almost always occur. This cavity also needs a horizontal cavity barrier at the compartment floors, but this will in turn will impede drainage or evaporation in the cavity! None of the standard detailing worked out so far was acceptable to 1 of the approved inspectors we worked with, which sent us round in circles for several months!
Beyond this, understanding and keeping up with the changing requirements is challenging but essential, not to mention keeping up with government guidance from MHCLG and advice from other bodies such as Society of Façade Engineering/CWCT.
Challenge 4 - The cost of PI insurance
One consequence of the Grenfell tragedy is the increasing cost of professional indemnity insurance for consultants. The cost of insurance has risen by a factor of 10 in many cases, with reduced cover or no cover at all being offered to façade consultants, fire engineers, approved inspectors and cladding contractors as well. Without PI insurance these individual companies will find it practically impossible to continue in business. Yet, without these professionals and contractors the problems of flammable materials are apartment buildings will not be fixed! Much of the problem is as a result of the Government funding requirement that building owners pursue those originally involved in the design and construction of the building. I wonder what would happen if this requirement was dropped?
Challenge 5- Funding
The Government has now put in something like £5.1 Billion to finance recladding of apartment buildings and this is being administered by the MHCLG. Progress is being made with replacing flammable materials but eventually the Government funding will come to an end.
What happens after that point is not clear at the moment. The estimated cost of the required recladding of apartment buildings in the UK is much higher than £5 billion. Some have placed this at more like £14 billion. So will there be further funding? Or a loan scheme for Building owners or leaseholders? We must wait to see what action is taken.