Steel expanded metal mesh

Raised or flattened

Raised mesh keeps the strands standing out of the plane. That is what gives a walkway its grip, and what most guard and platform specifications assume. Flattened mesh is pressed through rolls after stretching: the strands lie flat, the sheet measures true thickness, and nothing catches a brush, a hose or a hand.

Flattening costs a little more because it is a second operation, and it loses some stiffness. Raised for floors and stairs, flattened for ceilings, filters, cladding and anything that gets wiped down.

SWM and LWM

Expanded mesh is measured by the short way of mesh (SWM) and the long way (LWM) — the inside dimensions of the diamond, across and along the strand direction. A 25 × 75 mm mesh is not a 25 × 75 mm hole in the way a punched hole is: it is measured inside the diamond, and strand width is quoted separately.

When comparing offers, compare SWM, LWM, strand width and base thickness together. Two sheets sold as "2 mm expanded mesh" can differ by 30 % in weight if the strand width differs.

Walkways, guards and lath

For walkway and platform work the specification is driven by load and support spacing, not by mesh size — send the span and the load and we quote to it. For machine guards the requirement is usually that a finger or a tool cannot pass through, which puts the limit on the LWM rather than the thickness.

The same product in thin gauge is expanded lath: the base for plaster and render, where the mesh holds the mortar and the key comes from strands standing out of the wall.

Cutting and finishing

Sheets cut cleanly with a plasma cutter or a guillotine; a laser is slower than expected on an open lattice. Hot-dip galvanizing after expansion covers every strand, including the cut edges of each diamond, which is what makes galvanized expanded mesh last outdoors.