Section depth and thickness

Thickness

In residential buildings the thickness of structural profiles typically starts at 0.8 mm and goes up to 1.6 mm. In larger, multi-storey buildings thicker sections occur.

This is the range that separates the technology from drywall profiles, which are around 0.4–0.6 mm and are not made to carry load. Why it is not drywall profile.

Section depth

The choice of depth serves two things at once:

• structural: greater depth allows greater bending stiffness and longer spans,
• building physics: the section depth provides the space for insulation within the plane of the structure.

So wall thickness does not depend on the structure alone but on the build-up as well.

How much is enough

There is no general answer, because capacity comes from thickness, steel grade, geometry and restraint together. One reference point from practice: a wall made from 90 mm, 1.0 mm profiles already counts as load-bearing in a single-storey house — the exact figure depends on the span and on how many walls can be brought into the structural system.

That last part is the key: the more wall panels working together, the less action falls on any one member.

Why the wall can be thinner than in conventional construction

Because the structure and the insulation are in the same plane: the insulation sits between the sections rather than alongside the load-bearing layer.

For the same thermal performance the whole wall can therefore be far thinner than in conventional technology — roughly half, though the exact ratio depends on the build-up. Comparing wall thicknesses.

The design lesson

We do not choose one section size for the building; we put what is needed everywhere. The design work and the accuracy of production are what keep this from complicating construction: every member arrives marked and cut to size.

The point

It is not the size of the section that decides whether something is load-bearing, but how the whole structure works together. That is why the structural engineer belongs in the project at concept stage.