Façade companies like Maple typically work to tolerances of as little as 1mm. The National Structural Steelwork Specification for Building Construction (NSSS) says 10mm is good enough. That’s a problem, right?
In a nutshell:
- Tolerances on an architectural façade project could be as little as 1mm
- British Standards and the NSSS specify tolerances of 10mm
- Achieving smaller tolerances on structural steelwork could be expensive, difficult and even dangerous
- Specialist façade companies use adjustable brackets to compensate for any variation
- Collaboration between façade companies, architects, metal fabricators, contractors and specialist suppliers is paramount
On the face of it, yes it is. When installing architectural façades, rainscreen cladding and brise soleil, companies are striving to achieve the clean lines and perfect joints demanded by architects and clients. And if the steel support structure is off just a little...
What do the building regulations say?
There’s a reason the NSSS and Eurocode 3 (BS EN 1993: Design of steel structures) have specified tolerances of less than half an inch in old money. And it’s because 10mm on an office block or multi-storey car park is very small indeed. Asking steelwork contractors to take things to the next level would dramatically increase the cost of construction – and would be difficult and dangerous to achieve.
Why would they, anyway, when most of the steelwork is hidden from view? So, what happens? Façade companies are left (quite literally) to fill the gaps. Fortunately, they can.
What can façade companies do?
Specialist companies use adjustable brackets during installation to compensate for any variation in the sub-structure. So-called ‘helping hand’ brackets (some with reusable components) are used to hold panels in place before final fixing.
It's the reason façade companies can assure architects they can turn their often demanding concepts into buildable reality – but it also requires collaboration with sheet metal fabricators, laser cutting contractors and suppliers to achieve these same minimal tolerances.
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