Five things that go wrong with rainscreen cladding – and how to avoid them
Rainscreen cladding is more than decoration. Behind every finished panel is a complete system made up of support structures, fixings, insulation, membranes, fire barriers, and interfaces.
That means if you get one part wrong, the consequences can affect everything from the appearance of the building to its structural integrity, fire safety, and performance. Over the years, I’ve seen the same issues come up time and again in facade construction.
Here are five of the most common – and what contractors should be doing differently.
1. Getting the finish selection wrong
Finish selection is incredibly important, but often overlooked. There are plenty of impressive brochures and samples to choose from, but finishes can behave differently when they are applied across an entire building.
Colour can look different depending on the base material. Gloss can change depending on orientation. Metallics can be particularly challenging if the way the finish is applied changes between longer panels and corners.
So finish selection can’t simply be about choosing a colour from a brochure. Texture, gloss, material, and orientation need to be considered before the specification becomes difficult to change.
2. Choosing the wrong support structure and fixings
The finished panel gets most of the attention, but what sits behind it is just as important.
There are a wide variety of support structures available. The right one needs to be selected for the finished panel, presenting substructure, building orientation, and weatherproofing strategy.
Failure to do so can create structural problems, make it difficult to achieve an effective fire barrier, or affect the appearance of the finished facade through issues such as oil canning.
Fixings matter, too – massively. Poor material selection or mixing incompatible materials can lead to accelerated deterioration. The support system also has to work with other elements behind the cladding, such as membranes, insulation, and vapour barriers.
3. Ignoring thermal and building movement
Thermal movement is easy to overlook as you don’t necessarily see the consequences on day one. Buildings experience changing temperatures, direct and indirect sunlight, wind, and structural movement. Different materials respond differently to those conditions. And when they’re combined, that needs to be understood in the design.
Steel and aluminium, for example, can be used together, but you have to account for their differential movement. The design of the fixings, including the holes around those fixings, can be critical in allowing that movement to happen safely. Otherwise, you can end up with oil canning, metal fatigue, corrosion, or, in the worst cases, panels becoming insecure.
If something hasn’t been designed so that it can actually be put together properly on site, the installer can be left trying to find a solution. That’s when shortcuts become tempting, and the integrity of the whole system can be compromised.
4. Treating fire compliance as a paperwork exercise
There’s a whole series of categories, technical data sheets, and evidence involved in fire compliance. All of that is important. But compliance must exist in practice as well as on paper.
The facade needs to work as a complete design. It’s possible to create something that works from a fire perspective but creates a problem with vapour control, for example. Equally, projections and unusual areas of a building can introduce challenges that aren’t solved simply because the individual products have the right paperwork.
That’s why fire safety has to involve experience and competence as well as evidence. What is designed has to be practical and buildable so that what gets designed is what actually gets built. The Golden Thread is an important part of that. Every critical detail needs to be installed correctly and recorded so there is evidence that the work has been carried out with integrity at every stage.
5. Losing detailing integrity at the interfaces
You can have a strong architectural concept, a clear elevation, and a well-considered facade – only for the design intent to fall apart when you get into the details. And the interfaces are where it becomes difficult.
Windows. Masonry. Roofs. Doors. Lighting. Balconies. Soffits. These are the points where different packages and responsibilities meet, and where the integrity of the original design can easily be lost. That’s why we spend so much time looking at the whole detail rather than simply the panel we’re responsible for.
Doing the job right
These five problems might look separate, but they’re closely connected. The consequences might not appear immediately. Problems can be picked up later by the regulator or warranty provider, increasing completion and maintenance costs, or compromising the appearance and performance of a building.
That’s why our approach at LockMetal comes back to three things: beautiful, buildable, safe.
For me, buildable means making it easier to do the job right than to do it wrong. Safe means making sure critical details are installed correctly, recorded, and evidenced. And beautiful means protecting the architectural intent for the life of the building.
