Skim Coat is a high-bond strength, fast-curing, smooth hydraulic cement-based material for underlayments, concrete repairs, patching, and skim coating on interior and exterior projects. Use the product to repair level and smooth concrete substrates before installing floor coverings such as vinyl composition tile, sheet vinyl, carpet, tile, pavers, epoxy topping, and other coatings. CTS Cement. 800-929-3030.