No Organic Solvent Water-based Polyurethane Waterproof Coating For Enclosed Space Water‑based Polyurethane Waterproof Coating Construction Procedure Substrate Preparation Make substrate solid and flat. Remove dust, oil and loose mortar. Repair cracks and holes with repair mortar. Damp substrate is acceptable, standing‑water is forbidden. Detail Reinforcement Apply 1‑2 coats of coating as extra reinforcement layer for corners, pipe roots, floor drains and construction joints.