Aluminium expanded mesh

What it is

Aluminium expanded mesh is sheet aluminium slit and stretched into a continuous diamond pattern, in the same way as steel expanded metal. It weighs roughly a third of an equivalent steel mesh, does not rust, and takes anodising and powder coating well, which makes it a favourite material for architects: car park and building facades, sunscreens and shading fins, feature ceilings, plant screens, fence and gate infill and balustrade infill.

The diamond strands are set at an angle, so a facade of expanded mesh looks solid from one direction and open from another, and admits daylight and air while reducing solar gain and screening what is behind. Flattened mesh gives a smoother, more graphic surface; raised mesh casts deeper shadows.

Types and options

Panels can be framed in aluminium extrusions or in galvanised steel angle and channel, and fixed with brackets to the building frame, canopies or a dedicated sub-frame. Perforated sheet is an alternative where a flat, patterned face is preferred – see perforated metal panels.

Design and compliance

Facade mesh is a cladding element and is designed for wind like any other. Wind actions on panels, frames and brackets come from AS/NZS 1170.2, ASCE 7 or EN 1991-1-4, using the pressure coefficients the engineer adopts for porous screens; deflection limits and fixing spacing follow. Aluminium members are designed to AS/NZS 1664, the Aluminum Design Manual in the US or EN 1999-1-1, and steel sub-frames to AS 4100, AISC 360 or EN 1993-1-1. Contact between aluminium and carbon steel or stainless is isolated to avoid galvanic corrosion.

Fire rules must be checked early. Aluminium itself is non-combustible, but coatings, backing materials and the wall build-up count. In Australia the NCC limits combustible materials in external walls of Type A and B construction, with non-combustibility tested to AS 1530.1; in Europe reaction-to-fire classes follow EN 13501-1; in the US, NFPA 285 applies to exterior walls with combustible components. Test evidence for a mesh, coating or facade system is product-specific and comes from the manufacturer – World Steel does not hold fire tests of its own. See fire protection for background.

Fabrication and finishing at World Steel

Aluminium expanded mesh is produced by specialist mills and supplied by World Steel with the project package. We cut the mesh to the panel schedule, fold or trim edges, and fabricate the frames, brackets and sub-frames: steel parts are welded in the World Steel plant to ISO 3834-2 procedures under our AS/NZS 5131 and EN 1090-2 systems, then hot-dip galvanised by qualified galvanisers. Anodising and architectural powder coating of the aluminium are carried out by specialist finishers to the specified standard, and colour batches are kept together per elevation.

Panels are interleaved, edge-protected and crated by elevation and level for export shipping, so a facade crew can install them in sequence.

Selecting and specifying

• Start from the design intent – shade, view-through, ventilation, screening – and choose pattern and orientation with a sample.
• Give the wind region or basic wind speed, building height and terrain so panels and brackets can be sized.
• Name the finish standard, colour and gloss, and any warranty the architect requires from the finisher.
• Confirm facade fire requirements with the building certifier before the mesh and coating are ordered.