MasterSeal® 620 Non-Fibrated Bitumen Emulsion — Damp-Proofing Coating
Two-component, cold-applied polyurethane liquid membrane that cures to form a seamless, highly flexible, and fully elastomeric waterproof coating for below-ground structures, wet areas, roofs, and internal damp-proofing applications. Chemical curing system — does not rely on atmospheric moisture.
RTU
No mixing, heating, or preparation required. Open the drum, apply by brush or squeegee directly from the container. Non-flammable. Zero VOC. Can be applied on fresh concrete and slightly damp surfaces.
Performs reliably under sustained 45°C+ summer temperatures with a wide service temperature range of –30°C to +100°C and application temperature up to +55°C. Engineered for coastal UAE environments including Abu Dhabi and Dubai, where salt-laden humidity and high ambient temperatures require a product that can be applied on damp substrates without losing adhesion or waterproofing integrity. Suitable for hot and tropical climatic conditions.
UAE's trusted construction chemistry partner — expert coordination, authentic supply, site-ready delivery.
What is MasterSeal® 620?
MasterSeal® 620 is a single-component, thixotropic bitumen/rubber latex emulsion supplied ready to use in 200-litre drums. Requiring no mixing or heating, it is applied by brush or squeegee directly from the container to form a tough, seamless, flexible, and fully damp-proof and vapour-proof black membrane on concrete, masonry, and a wide range of construction surfaces.
With 10% rubber content in the dried film, it combines the waterproofing durability of bitumen with the crack-accommodating flexibility of rubber latex. Non-flammable, zero VOC, and approved for application on fresh concrete and slightly damp surfaces. Its multi-purpose nature also makes it suitable as an adhesive for insulation boards, cork tiles, and wood mosaics — and as a vapour barrier on roofs.
Key Performance Benefits
- Single component — ready to use with no mixing, heating, or preparation required
- Forms a seamless, flexible, damp-proof and vapour-proof black membrane
- Can be applied to fresh concrete and slightly damp surfaces
- Non-flammable and zero VOC — safe for enclosed spaces and hot weather sites
- Wide service temperature range of –30°C to +100°C — suited to extreme UAE climate
- 10% rubber content — combines bitumen durability with rubber crack-bridging flexibility
- Thixotropic — easy brush or squeegee application with minimal sag on vertical surfaces
- Multi-purpose: waterproofing membrane, vapour barrier, and adhesive for insulation/tiles
- Suitable for hot and tropical climatic conditions — ISO 9001 / 14001 / 45001 certified
Typical Applications
Chemical & Physical Properties
| Composition | Thixotropic cold-applied bitumen emulsion with added rubber latex |
| Appearance (wet) | Dark brown liquid |
| Appearance (dried) | Black seamless membrane |
| Density | ~1 kg/litre @ 25°C |
| Rubber Content (dried film) | 10% |
| VOC Content | Nil |
| Flashpoint | Non-flammable |
| Fire Classification | BS EN ISO 11925 Part 2 / BS EN 13501 Part 1:2007 + A1:2009 |
| Service Temperature | –30°C to +100°C |
| Application Temperature | +5°C to +55°C |
| Shelf Life | 12 months (unopened, stored properly) |
| Quality Certifications | ISO 9001 / ISO 14001 / ISO 45001 (Master Builders Solutions) |
Application Parameters
| Mixing | Not required — single component, ready to use |
| Application Method | Brush or squeegee |
| Minimum Coats | 2 coats minimum |
| Coverage per Coat | 1.5–2.0 m²/litre (substrate dependent) |
| Drying Time (+20°C) | 3–5 days |
| Substrate Condition | Damp acceptable — not waterlogged |
| New Concrete | Applicable on fresh concrete |
| Min. Application Temp | +5°C |
| Max. Application Temp | +55°C |
Packaging — UAE
| 200 Litre Drum | Standard supply for medium-to-large project volumes |
Application Guide — UAE Site Conditions
Follow these steps for optimum damp-proofing and protective coating performance with MasterSeal® 620 in UAE's hot, coastal, and high-humidity environments.
Surface Preparation
All surfaces must be sound and stable with an even finish, and free from dirt, dust, loose debris, and grease. The product may be applied to damp but not waterlogged surfaces. Hot, very dry, or porous surfaces should be dampened with a priming coat before application to reduce rapid absorption and ensure good adhesion of the first coat.
Application
MasterSeal® 620 may be applied by brush or squeegee directly from the container — no decanting or preparation is required. Apply in a uniform, even layer, working the material well into any surface irregularities. Where subsequent coats are to be applied, the first coat must be dry. Apply subsequent coats in a crosswise direction to the previous coat to ensure complete, pinhole-free coverage.
Curing & Overcoating
MasterSeal® 620 should be allowed to dry for 3–5 days before overcoating, tiling, or placing protection layers. Drying takes longer in low temperatures and high humidity. Providing good ventilation will significantly reduce drying time. Ensure each coat is fully dry before applying the next — touching the surface should leave no marks before proceeding with subsequent coats or protection.
Cleaning
Before MasterSeal® 620 has dried, clean all tools and equipment using soapy water immediately after use. If the material has already dried, remove by scraping mechanically and with paraffin or white spirit. Do not leave material on tools — dried bitumen emulsion is difficult to remove mechanically once cured.
Storage on Site
Store in undamaged, unopened, original sealed packaging in dry conditions at temperatures between +5°C and +35°C. Protect from direct sunlight, heat, and moisture. As with all bitumen emulsions, some settlement will occur with prolonged storage — stir before use if settlement is visible. Do not allow product to freeze.
Hot Substrate
Do not apply when substrate temperature exceeds 55°C. Surfaces above 55°C in UAE summer midday sun cause flash evaporation of the water carrier — preventing proper film formation and adhesion. Pre-wet and apply in early morning.
Storage Temperature
Store between +5°C and +35°C. Never store outdoors in direct UAE summer sun — drum temperatures will exceed product limits, accelerating settlement and degrading emulsion stability. Always store in shaded, cool warehousing.
Waterlogged Surfaces
MasterSeal® 620 can be applied to damp surfaces but not waterlogged substrates. Standing water or running moisture prevents the emulsion from adhering to the surface — active water must be diverted or stopped before application.
Recommended System Products
Combine MasterSeal® 620 with these Highway BMT-stocked products for complete below-grade waterproofing, concrete protection, curing, and joint sealing systems across UAE construction projects.