I. Clarify Needs and Match Scenarios
Long-term water-immersed areas (such as basements, pools): Polyurethane waterproof coatings with strong water resistance should be selected. They have a high elongation rate (usually ≥450%) and can resist expansion and contraction caused by water pressure changes.
Kitchens and bathrooms: It is recommended to use the "rigid walls and flexible floors" combination - polymer cement-based waterproof coatings (JS coatings) for walls, which are rigid and can be directly tiled; acrylic waterproof coatings for floors, which have good elasticity and can adapt to the deformation of the base layer.
Exposed roofs: Prioritize acrylic or silicone rubber coatings with excellent weather resistance, which can withstand ultraviolet radiation and cold-heat cycles to avoid cracking.
The low-temperature flexibility of acrylic waterproof coatings should reach -10°C without cracks, and some high-end products (such as Oriental Yuhong high-elastic thick acrylic ester coatings) can achieve no cracks when bent at -15°C.
Cementitious capillary crystalline waterproofing coatings are suitable for construction on damp base surfaces and can maintain bonding strength in low-temperature environments.
II. Verify Standards and Strictly Control Quality
Current general standards: GB/T 23445-2009 (polymer cement waterproof coatings), JC/T 864-2015 (polymer emulsion waterproof coatings).
New mandatory standard (to be implemented in November 2025): GB 45671-2025 "Safety Technical Specification for Architectural Waterproof Coatings", which requires solvent-based coatings to have VOC ≤700g/L, water-based coatings to have VOC ≤50g/L, and adds tests such as low-temperature performance after thermal aging and artificial weathering. It is recommended to prioritize products that have passed the testing of this standard (such as Keshun Lvyou L400).
Environmental certifications: China Environmental Label (Ten-Ring Certification), GREENGUARD Gold Certification (such as Keshun Lvyou L400), the latter has stricter limits on TVOC and formaldehyde (formaldehyde ≤0.05ppm).
Test reports: Check recent third-party testing data, focusing on tensile strength (JS coatings ≥1.2MPa), elongation at break (acrylic coatings ≥300%), and water impermeability (0.3MPa/30min without leakage).
III. Preferable Brands and Risk Avoidance
Oriental Yuhong: Ranked first in the engineering market share, with products covering all scenarios, such as HCA-101 acrylic coatings.
Keshun: Outstanding performance in the home decoration field, with the Lvyou series passing strict environmental certifications.
Davco: Advocate of the "rigid walls and flexible floors" solution, with the K11 universal waterproof coating enjoying high market recognition.
Nippon Paint: Rich color options, suitable for decorative waterproofing of exposed walls.
Avoid products with incomplete packaging labels (such as no production date or execution standard).
Be wary of low-price traps: Polyurethane coatings with a unit price lower than 20 yuan/kg may have quality hidden dangers (qualified products are usually ≥30 yuan/kg).
IV. Channel and Acceptance Points
Official channels: Brand official websites can query the list of authorized dealers to avoid buying counterfeit products. For example, Davco has exclusive stores in Handan, providing anti-counterfeiting inquiry services.
E-commerce platforms: Prioritize brand flagship stores and pay attention to checking the PDF files of test reports in the "product details".
Building materials markets: Recommend regular stores such as Handan Yuexing Home Furnishing and Red Star Macalline, and choose merchants with fixed stores.
Unpacking inspection:
Packaging tightness: Check for signs of secondary packaging, and the coating should be free of stratification and precipitation.
Quality guarantee card and test report: Request the merchant to provide the original or scanned copy with the official seal.
Construction supervision:
Base layer treatment: Ensure the base surface is flat and dry (moisture content ≤8%), and 阴阳角 are treated with arcs.
Brushing process: Use the "cross method" to brush 2-3 times, with a total thickness of ≥1.5mm. Polyurethane coatings need to dry for 6-8 hours before applying the next coat.
Water tightness test: Conduct it 48 hours after completion, with a water level of ≥2cm, and observe whether there is leakage in the corresponding position downstairs.
V. Environmental Protection and Health Assurance
Prioritize water-based coatings, which have low organic solvent content (usually ≤5%) and little odor. For example, Sankeshu waterproof mortar has a VOC content of ≤10g/kg, meeting the standards for children's rooms.
Avoid solvent-based coatings (such as tar-based polyurethane), which contain benzene substances and may cause respiratory diseases with long-term exposure.
VI. Solutions for Special Scenarios
VII. Common Misunderstandings and Pitfall Avoidance Guidelines
