How Not to Fail on Facades
For a decade and a half the construction industry has been going through a period of flux which has directly impacted the role of façade consultants and the growth of that role within the industry. Some of the causes of these changes are:
- Advancements made in manufacturing and material technology, and specifically the drive to manufacture offsite
- The need to lessen the duration of projects through the use of differing methods of construction, access and handling
- Environmental and sustainability concerns
- Geometrically challenging aesthetics
As with many other elements in construction, the days of simple elemental layered facades are long gone. A modern façade tends to combine new engineered materials into ever more complex systems. Systems which are being assembled in untried combinations with other modern methods of construction (MMC), or which abut more traditional types of façade treatments. Untested unique and bespoke building interface arrangements have an increased risk of one or more of their performance parameters failing.
Common risks faced when using Modern Methods of Construction
- More parts
- More interfaces
- Higher potential for material compatibility issues
- Less in-depth historic system knowledge
- More complexity of design / geometry
Understanding the complexities and vagaries of modern facades while ensuring that the façade itself is looked at holistically rather than elementally has become an important specialism. Façade consultants are now a contractual requirement on many projects.
A Façade Consultant ensures that both the aesthetic and performance requirements of the façade are attained during both the design and the installation stages of the build. It’s very important that a façade consultant with the right level and variety of experience for the project at hand is chosen.
It can be a real challenge to find a specialist contractor that can complete all elements of a façade and sometimes it may be totally impossible. For this reason, a buildings envelope may be split up by the main contractor into smaller parts and managed by several individuals. However, the issue with this is that having too many people working on the envelope can become detrimental to the project programme or façade performance.
Let us use a rainscreen wall as an example. On site we frequently see rainscreen walls being broken up into different groupings (rainscreen + insulation, cement particle board, structural framing system (SFS), vapour control layer and plasterboard etc.) with each of those groupings being managed and installed by a different specialist contractor. Because in this methodology there are many designers, managers and operatives involved in the production of this on façade element. We end up with a mass of conflicts and split design responsibilities within this ‘standard’ through wall element. These additional complications are further multiplied when this construction element abuts another one.
Though there are savings to be had by splitting up the façade package in the short term, these can be eroded very quickly by the additional cost of management, any site delays, additional costs from missed interface elements etc. The risk of longer term (legacy) failures is almost never taken into account when potential savings are tabled during the pre-construction phase. The cost to remediate a legacy, to essentially fix it, will be many times more expensive than the original cost.
There are a wide variety of reasons that can cause a façade to fail all of which are avoidable. In order to stand a chance of mitigating these potential failures it’s really important that the specialist contractor packages are carefully considered before being divided up. Before splitting up or allocating a specialist contractor take into account the capabilities of the specialist contractors, ensure that everyone knows what they’re doing, who has responsibility for what, and build up clear channels of communication.
New buildings need to have reduced air permeability, greater u-values and better waterproofing. To do this they rely heavily on gaskets, sealants, tapes and membranes. At junctions and interfaces it is very important that these elements are detailed and installed correctly and that the different specialist contractors that you’ve hired can diligently coordinate their work.
When managed properly and designed well, modern methods of construction can offer economic, rapid and robust solutions that were unobtainable with traditional methods.
Please Note: Every care was taken to ensure the information in this article was correct at the time of publication on 26.3.2018. However, for the most up to date LABC Warranty technical guidance please refer to your Risk Management Surveyor and the latest version of the LABC Warranty technical manual.