Welded wire reinforcement is specified by spacing and wire size, such as 6x6-W2.9xW2.9 for 6 in squares of wire with 0.029 sq in of area. It goes into slabs on grade, topping slabs and precast units for crack control and light structural duty. Field crews call it mesh or wire, and its classic failure is ending up on the dirt because nobody chaired it.
WWR on this slab is the flat sheets, not the rolls, so chair it at mid-depth and don't let anybody walk it flat.
Pulling mesh up with a rake during the pour, called hooking, rarely leaves it where it belongs; chairs do.
Also heard as
- welded wire reinforcement
- welded wire fabric
- WWF
- mesh
- wire
Related terms
Rebar
Deformed steel bar cast into concrete to carry the tension that plain concrete cannot.
Chair
A wire or plastic stand that holds rebar or mesh at the right height inside the form.
Drying shrinkage
The volume loss of hardened concrete as it gives up moisture over months and years.
Wild crack
An uncontrolled crack that wanders across a slab panel instead of forming under a control joint.