LGS fundamentals and materials

What this topic covers

The material and the section: which steel the frame is made of, what the coating means, what thicknesses we work with, what section shapes exist, and what separates this structure from hot-rolled steel or timber framing.

The governing idea

In one sentence: with thin-walled steel the bottleneck is not strength but stability.

A thick steel section is limited by the yield strength of the material. A section formed from 1 mm sheet is limited far earlier by the thin plate buckling, distorting and twisting. That difference explains:

• why the design method is different,
• why the accuracy of the cross-section matters so much,
• why it needs separate attention in fire,
• and why it cannot be thought of as “thicker drywall profile”.

How to read it

Start with what LGS is and how it differs from hot-rolled steel. Then the material: steel grade, yield strength, coating, corrosion. Finally the sections: what shapes exist, in what sizes, and what they are for.

If you want the structural behaviour, continue with the structural design topic.

What is not here

Load tables and a section catalogue. This knowledge base is for understanding; actual design is always produced for a project, from the manufacturer’s data.

The point

It is made from the same steel as conventional steelwork — but because it is thin, it behaves differently. That sentence is the key to the whole technology.