Purchase Estimator Enter the information below and press Estimate. NOTE: Enter numbers only. 1.5" Rebar Chair (911) 3" Rebar Chair (912) 3-Bar Footer Stand (924) 2-Bar Footer Stand (928) 2" Steel Mesh Chair (944) 1.5″ Rebar Chair (911) Length of Slab (feet) Width of Slab (feet) Rebar Spacing (inches) Estimate # of Chairs Required If rebar spacing is greater than 12", place chair at every rebar crossing. If rebar spacing is 12" or less, place chair at every other rebar crossing. Strength. Quality. SOLUTION.