Ⅰ.Core Principle
The water tightness test (flood test) must be performed only after the waterproofing membrane has fully cured. This ensures stable material performance and the complete evaporation of solvents, preventing false leakage readings or coating damage due to premature testing.
Ⅱ.Minimum Waiting Time for Water Tightness Test by Waterproofing Material Type
(Under standard conditions: 25°C, Relative Humidity ≤70%)
| Waterproofing Material Type | Minimum Waiting Time Post-Application | Key Rationale |
| Polymer-Modified Cementitious (JS) | 48~72 hours | Cement hydration requires 24 hours for initial completion; emulsion film formation requires >48 hours. |
| Polyurethane (Two-component) | 7 days | Full curing requires 7 days; early water exposure can cause blistering and delamination. |
| Acrylic (Water-based) | 72 hours | Surface dry: 2 hours; Through dry: 24 hours; however, full water resistance develops after 72 hours. |
| Epoxy Resin | 5~7 days | Slow curing reaction; achieves >90% cross-linking density after 7 days. |
| Bituminous Coating | 48 hours | Solvent evaporation requires 48 hours (can be reduced to 24 hours in high-temperature environments). |
| Crystalline Permeable Material | 3 days | Requires 72 hours for complete crystal growth within capillaries. |
Ⅲ.Pre-Test Inspection Checklist
1.Visual Inspection:
Coating is continuous, with no missed areas, blisters, or cracks.
2.Tactile Inspection:
Surface is not tacky to the touch and shows no imprint under light pressure (e.g., for polyurethane, gently scratching the surface should leave no mark).
3.Instrument-Assisted Inspection:
Coating Thickness Gauge: Verify the thickness meets specifications (e.g., ≥1.2mm for JS coatings).
Infrared Thermography: Detect any uncured/damp areas (a temperature differential >2°C indicates a need to postpone the test).
Ⅳ.Water Tightness Test Operational Standards
1.Water Depth:
Floor: Water depth ≥20mm (≥50mm in shower areas).
2.Test Duration:
Standard Areas (e.g., Bathrooms): ≥48 hours.
Critical Areas (e.g., Swimming Pools, Basements): ≥72 hours.
3.Pass/Fail Criteria:
PASS: No signs of leakage on the ceiling/area below, AND water level drop ≤ 2mm per day (accounting for evaporation).
FAIL: Any leakage observed OR excessive water level drop not attributable to evaporation.
