Grey Patch™ is a polymer-modified, calcium-aluminate, rapid-setting interior patching compound designed to fill voids and smooth surfaces of open concrete and approved wood underlayments. It can be used without a primer or additive, allowing for the installation of common floor coverings like VCT and carpet in as little as 1 hour. In the “skim-bond system,” Grey Patch™ is effective on cutback and non-water-soluble adhesive residue, single-layer, fully-bonded VCT, and other non-porous surfaces.