Welded wire fabric
Welded wire fabric is the sheet mesh form of reo (SL square, RL rectangular) to AS/NZS 4671, the standard slab reinforcement, laid in lapped sheets.
Ask Chalkline about this →Welded wire fabric is the mesh form of reo: prefabricated sheets of ribbed wire welded at every intersection, made to AS/NZS 4671. It is the standard reinforcement for residential concrete slabs, laid flat in sheets and lapped where sheets meet. It comes as SL square mesh (equal wire size and spacing both ways, e.g. SL72, SL82, SL92) and RL rectangular mesh (heavier main wires one way, e.g. RL818), with the engineer specifying the grade for the slab.
The two things that go wrong on site are cover and laps. The mesh must sit at the right concrete cover, typically 30 mm over a membrane and 40 mm to bare ground under the NCC Housing Provisions, held up on bar chairs; sagged mesh lying on the membrane is the most common pre-pour failure. Sheets must be lapped as specified by the engineer (not just butted up), so the reinforcement is continuous across the slab. Place it to the engineer’s drawings and get it checked at the pre-pour inspection.
Welded wire fabric (sheet mesh) reinforces the slab field; trench mesh is the long, narrow ladder-shaped mesh that runs in the thickened edge beams and strip footings. They are not interchangeable. See reo reinforcement for grades, laps, and the pre-pour checklist.
Also known as: Mesh, slab mesh, reinforcing mesh, SL/RL mesh.
Category: Materials / Concrete reinforcement.
Related
See also
References
- AS/NZS 4671:2019 Steel reinforcing materials, Standards Australia (verified 2026-05-08)
- AS 3600:2018 Concrete structures, Standards Australia (verified 2026-05-08)
Last updated: 2026-05-30. Verified: 2026-05-08. Quarterly review for currency.