UV-Resistant Polyurethane Waterproof Coat for Roofs

Product Overview

This single-component polyurethane waterproof coat is a moisture-cured, liquid-applied membrane designed for exposed roofs, terraces, balconies and roof refurbishment. After application, the polyurethane prepolymer reacts with moisture in the air to form a tough, flexible and seamless waterproof film.

The aliphatic polyurethane formulation provides strong ultraviolet resistance for outdoor exposure. The cured membrane adheres to properly prepared concrete, metal, wood, ceramic and other compatible substrates while accommodating normal thermal expansion and contraction.

Key Benefits

• Single-component formulation: ready to use without on-site component mixing.

• Seamless waterproofing: forms a continuous film around details, corners and penetrations.

• UV-resistant finish: suitable for exposed roofing and balcony applications.

• High flexibility: elongation helps the membrane accommodate substrate movement.

• Strong adhesion: bonds to multiple prepared construction substrates.

• Cold application: can be brushed, rolled, scraped or sprayed without open flame.

• Weather resistance: designed for hot and cold climates when applied under suitable conditions.

• Factory supply: available for contractors, distributors and OEM project requirements.

Typical Applications

• Exposed concrete roofs and roof maintenance projects.

• Terraces, balconies, podiums and parapet details.

• New and existing roof waterproofing refurbishment.

• Complex details around drains, pipes, upstands and equipment bases.

• Compatible metal, timber, ceramic and mineral substrates after preparation and primer selection.

Project suitability depends on substrate condition, moisture, climate, expected movement and service exposure. A site trial is recommended before large-area installation.

Product Classification and Packaging

• Classification: reactive-curing polyurethane waterproof coating.

• Standard color: light gray.

• Standard package: 20 kg sealed metal pail.

• Application methods: brush, roller, scraper or suitable spray equipment.

• Reference consumption at 1.0 mm thickness: approximately 1.4 ± 0.05 kg/m²; actual use varies with substrate profile and site conditions.

• Density: 1.25-1.35 kg/L at 23°C.

Technical Performance

The following values are based on the existing product test data. Project specifications and the latest technical data sheet should be confirmed before purchase.

• Solid content: requirement ≥85%; typical test result 90%.

• Surface dry time: requirement ≤12 hours; typical result 4 hours.

• Full dry time: requirement ≤24 hours; typical result 12 hours.

• Tensile strength: requirement ≥2.0 MPa; typical result 3.6 MPa.

• Elongation at break: requirement ≥500%; typical result 620%.

• Tear strength: requirement ≥15 N/mm; typical result 18 N/mm.

• Low-temperature flexibility: -35°C with no cracking.

• Impermeability: 0.3 MPa for 120 minutes with no leakage.

• Adhesion strength: requirement ≥2.0 MPa.

• UV exposure: tested according to ASTM G154 for 2,745 hours.

Application Guide

1. Prepare the Substrate

The substrate must be stable, smooth, clean and free from dust, oil, laitance, standing water and sharp projections. Repair cracks and defects, round internal corners where required and select a compatible primer for the substrate.

2. Treat Details

Apply additional polyurethane waterproof coating at corners, junctions, drains and pipe penetrations. Reinforcement fabric may be embedded where required by the project specification. Detail treatment should be completed before the main field application.

3. Apply the Main Coats

Stir the material uniformly before use. Apply multiple thin, even coats rather than one excessively thick layer. Alternate the application direction between coats and allow each layer to cure as specified. Verify consumption over a known area to achieve the required dry-film thickness.

4. Inspect and Protect

Inspect the cured polyurethane waterproof coat for pinholes, bubbles, thin areas and damage. Repair defects with compatible material. Protect the completed membrane from rain, contamination, traffic and following trades until it has fully cured.

Application Precautions

• Do not apply during rain, storms or when precipitation is expected before the coating cures.

• Heavy rain can damage material that is still in the liquid state.

• Do not apply to dusty, oily, unstable or unsuitable wet substrates.

• Provide ventilation in enclosed areas and follow the current safety data sheet.

• Do not add thinner, solvent or unapproved additives.

• Use compatible primers, reinforcement and protective finishes as specified.

• Application temperature, humidity and recoat time must follow the latest technical data.

Packaging, Storage and Transportation

The product is supplied in sealed metal pails with secured covers and caps. Store different grades and colors separately in a dry, well-ventilated indoor area. Protect the pails from direct sunlight, rain, collision and moisture.

Recommended storage temperature is 5°C to 40°C. Under normal sealed storage and transportation conditions, the stated shelf life is at least 12 months from the production date. Material beyond its shelf life should be retested before use, and prolonged high temperature may shorten storage life.

Frequently Asked Questions

Is this polyurethane waterproof coat suitable for exposed roofs?

Yes. The product is formulated with UV resistance for exposed roofs, terraces and balconies. Final suitability should still be confirmed against the project climate, substrate and expected service conditions.

How many coats are required?

Most liquid-applied systems use two or more coats. The required number depends on application rate, solids content and specified dry-film thickness. Coverage and thickness are more important than simply counting passes.

Can it be applied over an existing roof?

It can be used for compatible roof refurbishment after the existing surface has been inspected, repaired, cleaned and tested for adhesion. Unsound or incompatible layers must be removed or isolated with an approved system.

Can the coating be diluted?

No unapproved thinner or solvent should be added. Dilution can change curing, film thickness, adhesion and waterproof performance.

Project Support and Supply

Hongyuan supplies polyurethane waterproof coating for contractors, distributors and international projects. Send the roof type, substrate, climate, required thickness, application area and estimated quantity so the technical team can recommend packaging, primer and application details.

Selection guide: https://waterproofingbest.com/news/waterproof-coating-guide-types-applications-and-selection.html