Expanded
Metal
Industrial expanded metal manufactured by slitting and stretching a solid sheet into a rigid diamond-pattern mesh — stronger, lighter and more rigid than the original sheet. Available in large mesh, small mesh, security, super-rib render lath and agricultural grades. Mild steel, aluminium, stainless 304 and 316. Mill finish, hot-dip galvanised, Zincalume® and aluminium. Raised or flattened to suit your application.
The Process
How Expanded Metal Is Made
01
Solid Sheet Input
A solid flat sheet of mild steel, aluminium or stainless steel is fed into the expanding machine. No material is removed — the entire sheet is used, making expanded metal highly material-efficient.
02
Simultaneous Slitting & Stretching
The machine simultaneously slits and stretches the sheet in a single pass. Each slit is offset from the last, creating the characteristic diamond pattern. The process work-hardens the metal, increasing its strength.
03
Raised or Flattened
The as-expanded sheet has a raised (three-dimensional) profile. It can be left raised for anti-slip walkway and render lath applications, or passed through a flattening machine for a smooth flat surface.
04
Cut to Size & Finished
Sheets are cut to standard or custom sizes and finished — mill (uncoated), hot-dip galvanised, Zincalume® or aluminium. No welds, no joins — one continuous piece of metal.
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E-E-A-T Technical Reference
Expanded Metal Specifications
Terminology, dimensional definitions, material grades, finish specifications and applicable standards for industrial expanded metal.
Dimensional Definitions (AS 2423)
| Term | Abbreviation | Definition | Typical Range |
|---|---|---|---|
| Long Way of Mesh | LWM | The longer diagonal of the diamond aperture, measured from inside edge to inside edge | 9 mm – 102 mm |
| Short Way of Mesh | SWM | The shorter diagonal of the diamond aperture, measured from inside edge to inside edge | 6 mm – 50 mm |
| Strand Width | SW | The width of the strand (the metal bar forming the diamond sides), measured at the widest point | 1.14 mm – 5.6 mm |
| Material Thickness | T | The thickness of the original sheet before expanding. Equal to the strand thickness in the raised profile | 0.5 mm – 3.0 mm |
| Open Area | OA% | The percentage of the total sheet area that is open (void). Higher open area = more airflow, less weight, less material | 26% – 83% |
| Raised Profile | — | As-expanded; the strands are twisted out of the original sheet plane, creating a three-dimensional surface. Anti-slip; used for walkways and render lath | — |
| Flat Profile | — | Flattened after expanding; the strands are pressed back into a single plane. Smooth surface; used for screens, guards and architectural applications | — |
Strength-to-Weight Advantage
Stronger and lighter than equivalent flat sheet
The expanding process work-hardens the metal, increasing its yield strength. The diamond geometry distributes loads efficiently. Expanded metal is typically 30–50% lighter than solid sheet of equivalent structural performance.
No Welds or Joins
One continuous piece of metal
Unlike welded mesh, expanded metal has no weld intersections. The entire sheet is one continuous piece of metal — no weak points at joins. This makes it stronger in shear and more resistant to deformation under impact.
Security Mesh Anti-Climb
Small diamond prevents finger and tool grip
Security expanded mesh uses a small diamond aperture (LWM 16 mm × SWM 6 mm) that prevents fingers and tools from gaining purchase. The raised profile makes it difficult to cut with standard tools. Used in prisons, detention centres and critical infrastructure.
Super-Rib Render Lath
Mechanical key for render and plaster
Super-rib mesh has a pronounced raised rib that provides a mechanical key for render, stucco and plaster coats. Complies with AS 2904 (Lath — metal and expanded metal). Used in fire-rated wall systems and precast concrete panels.
Open Area & Airflow
High open area for ventilation and drainage
Open area ranges from 26% (12-25 profile) to 83% (50-30 profile). High open area profiles are used for ventilation grilles, drainage screens and applications where airflow or fluid passage is required.
Material Grades
Mild steel, aluminium, stainless 304 & 316
Mild steel (AS/NZS 1365) is the most common substrate. Aluminium (3003 or 5052 alloy) for lightweight and corrosion-resistant applications. Stainless 304 for food and pharmaceutical. Stainless 316 for marine, chemical and coastal environments.
Applicable Standards
AS 2423:1991
Expanded metal — steel
Primary Australian standard for expanded metal. Covers dimensional definitions (LWM, SWM, strand width, thickness), tolerances, open area calculation and material requirements for mild steel expanded metal.
AS/NZS 1365:1996
Tolerances for flat-rolled steel products
Covers thickness, width and flatness tolerances for the flat-rolled steel sheet used as the input material for expanded metal production.
AS 2904:1986
Lath — metal and expanded metal
Covers expanded metal used as render lath (super-rib mesh). Specifies minimum strand dimensions, open area and mechanical properties for render lath applications.
AS/NZS 4600:2018
Cold-formed steel structures
Referenced for structural applications of expanded metal — walkway panels, platform infill and structural screen applications where expanded metal acts as a load-bearing element.
AS 1650:1989
Hot-dipped galvanised coatings on ferrous articles
Covers zinc coating mass and adhesion requirements for hot-dip galvanised expanded metal. Minimum zinc coating mass 600 g/m² (both sides) for standard industrial applications.
AS/NZS 1554.1:2014
Structural steel welding
Referenced where expanded metal panels are welded into structural frames, walkway systems or security fencing assemblies.
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