MasterSeal® 550J Acrylic Cementitious Waterproofing Coating
Two-component acrylic-reinforced cementitious flexible waterproof coating designed to provide a flexible, seamless, and protective membrane for concrete and masonry surfaces. Manufactured at BASF's Dubai, UAE facility under ISO 9001, ISO 14001, and ISO 45001 certified management systems.
Manufactured at BASF's Dubai facility under ISO-certified systems, making it purpose-built for UAE and Gulf conditions. Performs reliably above 45°C, in high humidity, and under strong UV exposure. Resists chlorides, sulphates, saline groundwater, and atmospheric gases — ideal for coastal and below-grade structures across Dubai, Abu Dhabi, Sharjah, and Ras Al Khaimah. Key advantage: application on 24-hour-old concrete significantly accelerates fast-track UAE construction cycles.
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What is MasterSeal® 550J?
MasterSeal® 550J is a two-component, acrylic-modified cementitious coating composed of specially selected cements, silica sand, and reactive fillers in powder form (Part A), combined with blended acrylic copolymers and wetting agents in liquid form (Part B). Mixed on-site, it forms a hard-wearing, seamless, flexible, and fully waterproof membrane applicable by stiff brush, roller, or trowel to concrete, masonry, and most construction surfaces.
The "J" suffix denotes the Light Grey colour variant. Approved for contact with potable water (BS 6920: Part 1 2000). Manufactured at BASF's Dubai facility under ISO 9001, ISO 14001, and ISO 45001 certified management systems — purpose-built for UAE and Gulf site conditions.
Key Performance Benefits
- Fully waterproof — zero depth of water penetration under pressure (BS EN 12390 Part 8: 2009)
- Exceptional chloride ion resistance — diffusivity not measurable after 24 months of constant immersion
- Outstanding anti-carbonation protection — CO₂ equivalent air layer thickness (SD) >50 m
- Low liquid water permeability — <0.1 kg/(m²·h⁰·⁵) (BS EN 1062-3: 2008)
- Can be applied to 24-hour-old concrete — no 7–28 day cure wait required
- Excellent adhesion to porous and non-porous substrates without primer in most cases
- Breathable membrane — repels liquid water while allowing water vapour to escape
- Flexible and crack-accommodating — bridges minor substrate movement without delamination
- Non-toxic — approved for contact with potable water, tanks, cisterns, and water-retaining structures
- 550K White variant offers high Solar Reflectivity Index (SRI) for UAE rooftop applications
Slowly add Part A (powder) to Part B (liquid) in a clean container. Mix using a slow-speed drill with paddle mixer. Pot life is 60 minutes — do not mix more than can be used within one hour. Do not re-temper with water once mixing begins.
Chemical & Physical Properties
| Composition — Part A | Selected cements, silica sand, reactive fillers (powder) |
| Composition — Part B | Blended acrylic copolymers & wetting agents (liquid) |
| Colour | Grey (550J) / White available (550K) |
| Density | 1,940 kg/m³ |
| VOC Content | 0.5 g/L |
| Toxicity | Non-toxic — BS 6920 potable water approved |
| Water Penetration (pressure) | Nil (BS EN 12390 Part 8: 2009) |
| Liquid Water Permeability | <0.1 kg/(m²·h⁰·⁵) (BS EN 1062-3) |
| Chloride Ion Diffusivity | Not measurable after 24 months immersion |
| CO₂ Permeability (SD) | >50 m (BS EN 1062-6: 2002 Method A) |
| Chemical Resistance | NaOH, CaCl₂, de-icing salts, mild acids |
| Quality Certifications | ISO 9001 / ISO 14001 / ISO 45001 (BASF Dubai) |
Application & Site Parameters
| Mixing Ratio | 2 volumes powder : 1 volume liquid |
| Mixing Method | Slow-speed drill with paddle mixer |
| Pot Life | 60 minutes |
| Application Method | Stiff brush, roller, trowel, or spray |
| Min. Coat Thickness | 1 mm per coat |
| Coverage | 1.94 kg/m² at 1 mm thickness |
| Min. Application Temp | +5°C |
| Max. Storage Temp | 35°C (Part B liquid) |
| New Concrete (min. age) | 24 hours old |
Packaging — UAE
| 20 Kg Double Pack | Part A (15 kg powder) + Part B (5 kg liquid) — pre-measured kit |
Application Guide — UAE Site Conditions
Follow these steps for optimum waterproofing performance with MasterSeal® 550J in UAE's hot, coastal, and high-humidity environments.
Surface Preparation
Remove all grease, oil, dust, laitance, residual curing compounds, and mould release agents. Preferably remove laitance by light sweep blasting or hydro-jetting; mechanical wire brushing is acceptable for small areas. Cut back spalled concrete to sound substrate and repair with MasterEmaco S 488. Remove conventional curing compounds before application — MasterKure 181 is the only compatible exception. Roofing tiles must be firmly bedded and grouted before applying the membrane.
Mixing
MasterSeal 550J is supplied in pre-measured 20 kg double packs. Slowly add Part A (powder) to Part B (liquid) in a clean container and mix using a slow-speed drill with a suitable paddle. Mix ratio for part packs: 2 volumes powder to 1 volume liquid. Mix thoroughly and keep mixed during application. Pot life is 60 minutes. Do not mix more than can be used within one hour. Do not re-temper with water once mixing begins.
Substrate Condition Check
Saturate concrete surfaces with clean water until visibly damp but free of standing water — saturated surface-dry (SSD) condition. Do not apply to dry concrete. MasterSeal 550J can be applied to concrete as young as 24 hours old, significantly faster than the 7–28 day cure wait required by conventional coatings.
Application — First Coat
Apply MasterSeal 550J to the damp, prepared surface using a short, stiff bristle brush or roller at a minimum of 1 mm thickness per coat. Trowel application may be used where necessary. For heavy depressions of 6–10 mm (honeycombs, voids), reduce gauging liquid and mix to a stiffer consistency. For large areas, spray application is recommended — contact BASF Technical Service for appropriate spray equipment specifications. Coverage: 1.94 kg/m² at 1 mm thickness.
Subsequent Coats
Apply the second and any subsequent coats only after the previous coat has fully dried. Each coat must be a minimum of 1 mm thick. Apply in a crosswise direction to the previous coat to ensure uniform coverage and eliminate pinholes. Where tiling is to follow on vertical surfaces, contact the local BASF representative for advice on required membrane thickness and waiting time before tiling commences.
Curing & Storage
Protect the applied membrane from rain and water contact until fully cured. Store Part A (powder) clear of the ground in a dry, cool place away from direct sunlight. Store Part B (liquid) in a dry, cool, preferably air-conditioned warehouse below 35°C — do not stack Part B pallets. Clean all tools and equipment with clean water immediately after use; hardened material can only be removed mechanically.
Part B Storage
Do not store Part B (liquid) above 35°C. Heat shortens pot life significantly. Keep in air-conditioned storage during UAE summer — never leave on open site in direct sunlight.
Dry Substrate
Never apply to dry concrete. The substrate must be in SSD — saturated surface-dry condition. Dry surfaces will pull moisture from the coating, preventing proper curing and adhesion.
No Re-Tempering
Do not add water once mixing has begun. Do not exceed the 60-minute pot life. Mixed material that has begun to stiffen must be discarded — never re-tempered or thinned.
Recommended System Products
Combine MasterSeal® 550J with these Highway BMT-stocked Master Builders Solutions by BASF products for a complete waterproofing and protection system suited to UAE industrial and commercial environments.