I. Clarify the usage scenario and requirements
Different building parts (such as roofs, basements, bathrooms, exterior walls, etc.) have significantly different performance requirements for waterproof materials, so the usage scenario must be clarified first:
Roof waterproofing: It needs to withstand ultraviolet rays, temperature changes, and wind and rain erosion. Priority should be given to materials with strong weather resistance and high tensile strength (such as SBS modified asphalt waterproofing membranes, TPO polymer waterproofing membranes).
Basement waterproofing: It needs to resist groundwater pressure and has high anti-leakage requirements. Materials with good impermeability and strong adhesion are suitable (such as self-adhesive polymer modified asphalt membranes, cement-based 渗透结晶型 waterproof coatings).
Bathroom/kitchen: It is humid and may come into contact with water sources. Waterproofing must be combined with flexibility (to avoid cracking due to slight deformation of the base layer). Polyurethane waterproof coatings and JS composite waterproof coatings can be chosen.
Exterior wall waterproofing: It needs to withstand rain 冲刷 and climate aging. Elastic waterproof coatings (such as acrylic waterproof coatings) or waterproof and breathable membranes are suitable.
II. Pay attention to core performance indicators
Through product test reports or instructions, focus on the following key indicators:
Impermeability: The ability of the material to prevent water penetration is the core indicator of waterproofing, which must meet national standards (for example, the membrane is required to remain impermeable under 0.3MPa pressure for 30 minutes).
Tensile strength and elongation at break: They reflect the crack resistance and flexibility of the material. The higher the tensile strength and the greater the elongation at break, the better the material can adapt to base layer deformation (such as temperature changes, slight settlement).
Weather resistance/heat resistance/low-temperature flexibility: For outdoor use, attention should be paid to UV aging resistance (such as the results of artificial climate accelerated aging tests for membranes); materials in high-temperature areas need good heat resistance (such as asphalt membranes with high temperature resistance ≥80℃); materials in cold areas need good low-temperature flexibility (such as no cracks at -20℃).
Adhesion strength: For waterproof coatings or self-adhesive membranes, they need to be firmly bonded to the base layer (such as concrete, cement mortar) to avoid bulging and falling off.
III. Choose regular brands and channels
Check qualification certifications: Priority should be given to products that meet national mandatory standards (such as GB 18242-2008 "Elastomeric Modified Asphalt Waterproofing Membranes", GB/T 19250-2013 "Polyurethane Waterproofing Coatings"). Manufacturers are required to provide quality inspection reports and factory certificates.
Avoid "three no products": Be vigilant against low-cost materials without brands, labels, or test reports. Their performance is difficult to guarantee, which may lead to later leakage risks.
Refer to market reputation: Choose brands with a good reputation in the industry and perfect after-sales service to avoid difficulties in pursuing responsibility in case of after-sales disputes due to material problems.
IV. Pay attention to environmental protection and construction compatibility
Environmental friendliness: For indoor use (such as bathrooms, kitchens), materials with low toxicity and no pungent odor should be selected. Check the environmental protection test report of the product (such as VOC content meets national standards) to avoid excessive formaldehyde, benzene, and other harmful substances affecting health.
Construction convenience: Choose materials according to construction conditions. For example, small-area repairs are suitable for one-component waterproof coatings (no need for mixing); large-area construction can choose membranes (high efficiency); damp base layers need coatings that can be constructed on damp bases (such as cement-based waterproof coatings).
Compatibility with the base layer: The material must be compatible with the base layer material. For example, metal roofs are suitable for polymer membranes or special coatings with strong weather resistance; solvent-based materials should be avoided for wooden base layers (which may corrode wood).
V. Combine budget with long-term cost-effectiveness
Avoid excessive pursuit of low prices: Waterproofing is a "hidden project" of buildings. The quality of materials directly affects the service life. Low-cost materials may have a short service life (such as 1-3 years), and the later maintenance cost is higher; high-quality materials usually have a service life of 10-20 years, with better long-term cost-effectiveness.
Choose according to the service life: Temporary buildings can choose economical materials; permanent buildings need high-performance, long-life materials (such as polymer membranes, reactive waterproof coatings).
Summary
The core principles for selecting waterproof materials are: "scenario adaptation, qualified performance, reliable brand, and environmental safety". It is recommended to consult professional constructors before purchasing, comprehensively judge based on factors such as building parts, climate environment, and construction conditions. If necessary, manufacturers can be required to provide sample tests (such as a simple impermeability test: cover the material on a water cup and invert it to observe whether water seeps), to ensure that the material meets actual needs.
