Required as part of the HENRY 565 FloorPro Self-Leveling Installation System. HENRY 564 prepares the surface, improves the bond, and helps prevent pinholes and bubbles in the finished underlayment surface. For concrete, terrazzo, and burnished concrete with glass-like finish: Surface must be mechanically roughened prior to priming, shake primer well and mix 1:1 with water, apply with a soft bristle push broom - Do Not Use A Paint Roller - and allow primer to dry completely 3 to 24 hours. For wood subfloors: Apply with a short napped paint roller - Do Not Use A Push Broom or Dilute Primer - and allow primer to dry 16 to 24 hours. For ceramic tile: Glaze must be mechanically removed (such as grinding), apply full strength to unglazed tile using a soft bristle push broom - Do Not Use a Paint Roller - and allow primer to dry 12 to 24 hours to a clear, thin film. Coverage: 100 to 150 sq. ft. per quart. Quart bottle.