Structural and base materials

Metals in Construction

Metals turn up throughout a building: as frame, as reinforcement, as sheet roofing and cladding, as lath and mesh, and as the fixings that hold other materials in place. The questions that matter are usually about corrosion, compatibility and movement rather than raw strength.

Two themes recur. Different metals in contact, in the presence of moisture, can corrode faster than either would alone. And metals move measurably with temperature, which is why sheet metal roofing and cladding are detailed with movement in mind. Both are design matters for qualified professionals.

15 reference entries · educational materials reference · suitability always depends on the complete assembly and qualified professional review

Scope

What this category covers

Where the boundary of this part of the library sits, including what it deliberately leaves to qualified professionals.

Structural and light-gauge steel, reinforcement and decking
Corrosion-protected and corrosion-resistant metals used in the envelope
Non-ferrous sheet metals used for roofing, cladding and flashings
Not covered: structural sizing, connection design, corrosion-protection specification

Start here

Frequently referenced entries

A starting point, not a ranking — these are simply the entries most people arrive looking for.

Structural steel →Hot-rolled steel beams, columns and hollow sections used for primary structure, fabricated off site and connected on site by bolting or welding.Galvanised steel →Steel carrying a metallic zinc coating that corrodes in preference to the steel beneath it, which makes cut edges, drilled holes and site damage the real subject.Zinc sheet →Rolled zinc alloyed with small additions of titanium and copper, used as fully supported roofing and cladding and settling to a matt grey surface layer outdoors.

All entries

Every metals entry

The complete set for this category, in reference order.

Entry describes

Role in an assembly

Part of a building

Structural steel →Hot-rolled steel beams, columns and hollow sections used for primary structure, fabricated off site and connected on site by bolting or welding.

Light gauge steel framing →Cold-formed steel studs, tracks and joists roll-formed from thin coated coil, used for framing, infill walls and light structure rather than for primary beams.

Galvanised steel →Steel carrying a metallic zinc coating that corrodes in preference to the steel beneath it, which makes cut edges, drilled holes and site damage the real subject.

Stainless steel →Steel alloyed with chromium so that a thin passive surface film resists corrosion through the metal's own chemistry rather than through any coating applied to it.

Aluminium →A light metal used as rolled sheet, extruded profiles and castings, carrying its own oxide film and usually finished further by anodising or by powder coating.

Copper sheet →Rolled copper used as fully supported roofing, cladding and flashing, worked by folding and seaming, and changing colour steadily as a patina develops outdoors.

Zinc sheet →Rolled zinc alloyed with small additions of titanium and copper, used as fully supported roofing and cladding and settling to a matt grey surface layer outdoors.

Weathering steel →Low-alloy steel that forms a dense, adherent rust layer through repeated wetting and drying, used unpainted where its orange-brown surface is part of the design.

Steel reinforcing bar →Ribbed steel bar cast into concrete to carry tensile forces, protected from corrosion by the alkaline environment of the sound concrete cover surrounding it.

Profiled metal decking →Cold-formed profiled steel sheet spanning between supports as permanent formwork to a concrete floor, or as a structural roof deck carrying the build-up above it.

Metal lath →Expanded or perforated metal sheet fixed as a background for render and plaster, giving a mechanical key where the wall behind cannot provide one of its own.

Lead sheet →A dense, highly workable sheet metal traditionally used for flashings, valleys and weatherings, dressed to shape by trained trades who manage its handling considerations.

Cast and ductile iron →Iron poured into a mould and taking its shape as it solidifies, in grey and ductile forms whose graphite structures make them behave very differently when overloaded.

Structural fixings and anchors →Metal fixings that transfer load into concrete, masonry or steel, either cast into the structure before it is made or installed into a hole drilled in it afterwards.

Welded reinforcement fabric →Reinforcing wires or bars welded into a regular grid and supplied in sheets or rolls, where lapping at every sheet edge replaces the bar schedule as the thing that has to be right.

Browse by role

By the role the material plays

The same entries, clustered by what they typically do in an assembly. A material can appear in more than one cluster because it genuinely plays more than one role.

Structure

Materials that carry load or form the primary frame.

Substrate and base

Backgrounds and bases that other materials are fixed or applied to.

Weather barrier

Layers that shed or resist rain, wind and weather.

Moisture and air control

Thin layers that control where moisture and air are allowed to move.

Cast and ductile iron →

External surface

The visible outer face of a wall or roof.

Jointing and fixing

Materials that bond, seal, support or connect other materials.

Where they appear

Parts of a building this category touches

An orientation aid only — it does not imply that any entry is suitable for that part of a particular building.

Foundations and groundworks · 3
Structural frame · 10
External walls · 11
Roofs · 10
Internal walls and ceilings · 3
Floors · 6
Wet areas · 1
External works and landscape · 6

Elsewhere on Build Design Hub

Planning guidance for this subject

This library explains what materials are. These sections help with choosing between them and preparing for the conversation.

Exterior materials guides →Planning guidance for external walls, roofs and facades.Construction guides →How structural stages are planned and coordinated.Structural discussion preparation →Questions to prepare before a structural conversation.

Building Systems Encyclopedia

The assemblies these materials sit in

A material page explains what a substance is. These pages explain how the assembly around it is organised, what roles its components perform and which interfaces matter.

Structure and supportPrimary Structural Frames and Load-Bearing Wall Systems →Complete primary load paths from roof to foundation in masonry, timber, steel and concrete, together with the stability system without which none of them stands up.Building envelopeFacade and Cladding Systems →Outer skins carried on a wall that is already complete behind them, where the support, the joint and the cavity carry the durable knowledge rather than the finish.

Materials & Systems Encyclopedia

Reference entries for building materials, product formats and system components — what they are, what their behaviour depends on and what to ask about them.

Browse the full Materials Library →

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