What is sufficient PSI for underslab insulation to accommodate a 7,000-pound truck and a 9,500-pound skid steer?
The sufficient PSI for underslab insulation to accommodate a 7,000-pound truck or a 9,500 skid steer loader is 16 PSI. This value accounts for the point loads imposed by the truck and the skid loader as well as the uniformly distributed load coming from the concrete slab. Below is a breakdown of the loads and the strengths required to resist them.
CONCRETE SLAB LOAD
A typical, 6-inch reinforced concrete slab exerts a uniformly distributed load of 0.52 psi on a sheet of GPS insulation beneath it. This load causes less than 1% deformation in the GPS foam of an insulation product such as Halo Subterra.
7,000-POUND TRUCK LOAD
A 7,000-pound truck together with the concrete slab imposes a point load of 4.2 psi on the GPS foam board below the slab, contributing to a deformation of less than 2% in the foam. This level of deformation is well within the elastic limit of the insulation, meaning that the foam will return to its original thickness once the load is removed.
9,500-Pound Skid Steer Load
A 9,500-pound skid steer loader together with the concrete slab exerts 6.4 psi on the GPS foam board below. A load of 6.4 psi causes a deformation of fewer than 2%; again, this value is well within the material’s elastic limit.