WaterPU waterproof coating — also called polyurethane waterproof coating, waterborne polyurethane waterproofing, PU liquid membrane. It is a single-component, liquid-applied elastic membrane that cures by water evaporation and air moisture instead of solvent. It sprays or brushes on as a seamless film, works indoors and outdoors, and carries no solvent smell, which is why it has become the default choice for roofs, terraces, balconies, bathrooms, and basements in markets that no longer accept solvent-based coatings.
Choosing a PU waterproof coating manufacturer that actually produces the coating itself, rather than trading it, decides whether the film you receive matches the sample you approved.
What Is One-Component PU Waterproof Coating?
One-component water-based PU waterproof coating — also written as waterborne polyurethane waterproof coating, water-based PU waterproofing membrane, single-component water-based PU coating, 1K waterborne PU liquid membrane, PU dispersion waterproof coating, low-VOC elastic PU roof coating, spray-applied water-based PU coating, brush-applied PU waterproofing, seamless PU liquid rubber coating, elastic water-based PU wall coating is built on a modified polyurethane dispersion: solid polymer particles suspended in water, with no solvent carrier and no part A and part B to mix.
Well-known reference products include Sika Sikalastic-560, a one-component waterborne modified polyurethane membrane applied by roller, brush, or spray in white, grey, red, or terracotta, and its hot-climate version Sikalastic-560 GCC. Buyers often compare it with water-based acrylic systems such as Mapei’s Aquaflex range, which are cheaper but lower in elasticity, and with solvent-based PU, which still blisters on damp substrates.
Why the Film Comes Out Flat, Bubble-Free, and Crack-Free
Self-leveling. The coating has a low viscosity and a slow, even flow-out after application, so brush and roller marks level within minutes and the film dries to an even, flat surface instead of a ridged one. On horizontal surfaces this self-smoothing behaviour produces a professional seamless finish without extra labour.
No bubbling. A water-based film releases its carrier gradually as the water evaporates, so vapour escapes before the skin closes. Solvent-based coatings do the opposite: solvent trapped under a fast-sealing surface pushes up blisters as soon as the sun heats the roof.
No cracking. Elongation at break is typically around 350% in unreinforced films, with tensile strength in the region of 1.5 N/mm². The membrane stretches with thermal movement and bridges hairline cracks in concrete rather than splitting over them, which is why a correctly applied film still looks intact after a full seasonal cycle.
Excellent elasticity and film formation. The polymer coalesces into a continuous rubber-like layer that grips porous and non-porous substrates alike — concrete, mortar, brick, ceramic tile, aluminium, steel, zinc, timber, and aged bitumen. The film is also water vapour permeable, so the substrate can breathe without lifting the coating.
Weather and colour stability. UV-resistant pigments keep white and coloured films from chalking or yellowing on exposed roofs, and a white grade reflects heat, which lowers cooling load on a building.
Indoor and Outdoor Use, Applied by Spray or Brush
Outdoor use covers exposed flat and pitched roofs, terraces, podium decks, balconies, parapets, metal roofs, external walls, and refurbishment straight over old bitumen membranes. Indoor use covers bathrooms, kitchens, wet rooms, basements, plant rooms, and any wall or floor that will later be tiled. One product line covers both, which is what makes it easy for a distributor to stock a single SKU family instead of separate indoor and outdoor grades.
Application is straightforward. Stir the pail, dilute the first coat with around 10% clean water to use as a primer, then apply two or three coats by airless spray or by brush and roller at roughly 1.2–1.5 kg per square metre per coat, building 0.3–0.5 mm of dry film. Recoating takes 2 to 6 hours depending on temperature, the film resists rain after 4 to 8 hours, and full cure arrives in 2 to 4 days. Colour is made to order, so importers can hold white, grey, red, terracotta, or a house colour matched to their own brand.
BOSLAI: PU Waterproof Coating Exporter and Manufacturer
BOSLAI (Hangzhou Boslai New Materials Co., Ltd.) manufactures and exports polyurethane waterproof coating for interior and exterior use, and ships regularly to buyers in Vietnam, the UAE, Saudi Arabia, the Philippines, Thailand, Malaysia, Indonesia, India, Europe, Africa, and the United States. The coating is produced in several quality levels — economy, standard, and premium — so a distributor can serve a price-driven market and a specification-driven market from one supplier. As both a PU waterproof coating manufacturer and a PU waterproof coating exporter, BOSLAI handles export packing and labels for each destination market.
OEM and private label production is available: your brand on the pail, your label language, your colour, your carton and pallet design, and your packing specification from 5 kg, 10 kg, 20 kg, and 25 kg pails. Technical data sheets and safety data sheets are supplied on request, and free samples are available so importers can check flow-out, adhesion, elasticity, film appearance, and colour on a real job before committing to a container.
BOSLAI is currently looking for distributors, wholesalers, and importers with freight forwarding capability in these markets. If you already handle chemical cargo and want a cost-effective water-based PU waterproof coating to add to your portfolio, BOSLAI would like to work with you.
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FAQ
Q1: What is PU waterproof coating?
PU waterproof coating is a ready-to-use elastic membrane based on a polyurethane dispersion. It cures as the water evaporates, forms a seamless flat film by spray, brush, or roller, and suits indoor and outdoor waterproofing without solvent smell or mixing.
Q2: Can PU waterproof coating be used both indoors and outdoors?
Yes. The cured film is UV resistant and colour stable on exposed roofs and walls, and the coating contains no solvent, so it is also suitable for bathrooms, kitchens, basements, and occupied buildings where odour and VOC limits matter. One product covers both jobs.
Q3: Can BOSLAI customize colour and packaging for OEM orders?
Yes. BOSLAI produces water-based PU waterproof coating in custom colours and several quality grades, with private-label packaging, your own brand, label language, carton design, and packing specification from 5 kg to 25 kg pails, plus free samples and data sheets before ordering.
Q4: How do I choose a reliable PU waterproof coating supplier or exporter?
Choose a supplier that manufactures the coating itself, exports chemicals regularly, offers custom colours and OEM packaging, provides technical and safety data sheets before ordering, and ships free samples for adhesion and elasticity testing. BOSLAI meets all five requirements for global buyers.
Related Products
- Water-Based Polyurethane Waterproof Coating
- Bitumen Waterproof Coating
- Acrylic Waterproof Coating
- Concrete Surface Hardener (Primer)
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