A polymeric chair having a rebar cradle and legs of a T-shaped or U-shaped cross-section diverging downwardly from the cradle. The outer surface portions of the legs define segments of a cone. Inwardly extending web portions reinforce the legs and provide feet at the distal ends of the legs disposed to the inside of the outer surface portions. A flat sand plate for the chair has radially extending slots formed therethrough which are proportioned for snug engagement with side surface of the feet. The slots are elongate to accommodate different sized chairs having fee spaced at varying radial dimensions. The web portions taper to optimize their reinforcing function and conserve material. In one embodiment, a ring is formed integrally with the legs intermediate the table and the distal ends of the legs. The chair is of a unitary construction and may have an integrally formed strap for extension over the cradle to secure a rebar in place.