Metal spider bar chairs or wire bar chairs are perhaps the earliest known method of supporting reinforcing in concrete. The 4-legged, factory welded, steel chair has an indentation in the top to support rebar or mesh.
The chairs legs are dipped in a light grey plastic to prevent rust and to provide minimal exposure on precast and off-form concrete. Their strong and stable construction makes them ideal for use in precast, tilt-up, suspended and off-form applications. For slab-on-ground applications, a metal “Pizza” plate can be used to support the chair preventing the chairs from sinking into the sub-base.