Check subfloor to see if areas need to be removed. Remove the Damaged Floor Material. ... Add the Support Framing as Needed. ... Measure and Cut the Plywood. ... secure plywood to joists. ... Easily patch, repair and skimcoat indoor surfaces with Universal Patch and Skimcoat. This underlayment sets in 30 minutes 2 hours and 24hrs can be used on concrete, wood and metal flooring as a feather-edge, deep fill or embossing leveler. For patching and repairing indoor surfaces prior to flooring installation. Non shrinking reduces install time None sanded formula trowels easy for smooth finish High compressive strength exceeds 5,000 psi Approximately covers 40 sq. ft. We provide solutions to subfloor challenges ranging from the routine to the critical with our primers & moisture mitigation systems, repair products, floor leveling compounds, adhesives, and water proofing materials.