1. Material Requirements: Use one‑component or two‑component polyurethane waterproof coating, together with matching primer/adhesive materials. All materials shall comply with relevant environmental and performance standards. Store materials in a cool, dry place at 5–35 °C.

2. Substrate Conditions: The substrate shall be solid, flat, and of adequate strength, free from loose particles, surface powdering, or peeling. Seal around pipe roots, floor drains, and similar areas with sealing materials. Fill holes and cracks to a flat surface. Remove oil, dirt, and dust. Moisture content ≤9%, with no water seepage on the surface.

3. Application Environment: The ambient temperature must be above 5 °C, with no rain or snow. Provide good ventilation. The work surface shall be prepared with proper drainage.

1. Substrate Preparation: Remove loose mortar and dirt with a scraper, then sweep away dust with a broom. Remove oil stains using a wire brush and sandpaper. Fill depressions with 1:3 cement mortar to achieve a level surface.

2. Apply Primer: For two‑component products, mix thoroughly according to the weight ratio; for one‑component products, dilute as per instructions. Apply evenly using a roller or brush (approx. 0.2 kg/m²). Ensure uniform thickness. Allow to dry for at least 4 hours.

3. Detail Reinforcement Layer: Mix the waterproof coating according to the specified ratio. Apply an extra coat (reinforced layer) to critical areas such as pipe roots, floor drains, and internal/external corners. Ensure full coverage without missed spots.

4. Apply Coating Membrane: First coat: Mix the coating according to the ratio. Apply with a rubber trowel, spreading evenly (0.8–1.0 kg/m²). Work from the inside toward the exit. Second coat: After the first coat has cured until no longer tacky, apply the second coat in a direction perpendicular to the first (0.8–1.0 kg/m²). After the second layer cures, apply the third layer at a rate of 0.4–0.5 kg/m². The total thickness should meet design requirements, typically between 1–2 mm.

5. Water Immersion Test: After the coating membrane has fully cured (typically 7 days), conduct a 24‑hour water immersion test. The project is considered qualified if no leakage is detected.

The coating membrane shall be uniform, free from pinholes, bubbles, and cracks. Details shall be properly treated with no leakage. The coating shall bond firmly to the substrate with no peeling. Total thickness shall meet design requirements.