Our build-up guidelines

What we will design any time

Practically any build-up that complies with the regulations. If the client’s expectation is low cost, we will design that too — but they have to know what they are taking on.

Two guidelines we stand behind

1. The board layer goes outside

A doubled wall with cement board on the outside — not insulation. The outermost layer should be hard and impact-resistant.

If we already have a board that provides hardness, let it be the outermost layer. The common counter-example — OSB outside with polystyrene on it — puts the layers exactly the wrong way round. Board materials: what belongs where · Continuous external insulation · Organic and absorbent materials in the wall.

2. The cabling does not run between the profiles

In light gauge steel construction vapour control is done solely by the membrane. Every hole drilled for a light switch is a hole in that envelope.

Machine makers like to advertise punching the profiles, but we do not recommend it — partly for fire reasons, partly because of the vapour control.

Instead: fire-rated board and the vapour control membrane on the inside face of the structure, with the installation inside that, in a second plane formed with battens. It costs 30–40 mm across the wall. Service cavity · Web holes and service openings.

What this means for shop design

The build-up is not decoration: the fixing of the lining and the bracing are linked. If the lining has a bracing role, the board type and the screw pattern are designed values that the shop drawings and the erection drawings have to carry. Sheathing diaphragm.

The full account

We have written in detail about build-ups, sound insulation, floors and cable routing in the technology knowledge base. Building physics and build-ups.

The point

Two guidelines, and both say the same thing: the hard layer outside, and the envelope stays intact. The rest depends on the requirements.