MasterSeal® 551 Cementitious Waterproof Coating | MCT CHEMICALS | MASTER BUILDER SOLUTIONS

Recommended Uses
MasterSeal 551 is ideal for:

• Waterproofing roofs, decks, balconies, etc.
• Water-retaining structures exposed to movement
• Basement waterproofing
• Protecting concrete from water, carbonation, and de-icing salts

Features and Benefits

• Carbonation Protection: A 1mm layer offers anti-carbonation coverage equivalent to more than 80cm of concrete.
• Waterproof: Suitable for both internal and external waterproofing applications.
• Excellent Adhesion: Bonds effectively to both porous and non-porous surfaces.
• Flexibility: Accommodates the thermal movements of concrete structures.
• Potable Water Contact: Safe for use in concrete water tanks.
• Vapour Permeable: While repelling water, it allows the concrete to breathe, preventing osmosis.
• Moisture-Resistant: Can be applied to concrete that is up to 24 hours old, offering immediate protection.
• Durable: Suitable for occasional foot traffic.

Standards

• BS 1881 Part 208: 1996 – I.S.A.T.
• DIN 1048 water penetration test

Surface Preparation
For optimal performance, surfaces must be structurally sound, clean, and free from laitance, loose particles, oil, grease, old coatings, curing compounds, and other contaminants. The direct tensile strength should exceed 1.5MPa as measured by a pull-off tester (100N/s load rate). In small areas, mechanical wire brushing may be appropriate. For irregularities, use MasterEmaco repair mortars to create a smooth, level surface before priming.

Mixing
MasterSeal 551 is supplied in pre-measured units, and should be mixed on-site in clean containers. Slowly add the powder to the liquid and mix using a slow-speed (300rpm) drill with a suitable paddle. Only mix the amount that can be used within an hour. Do not apply to dry concrete. Ensure the surface is damp (saturated surface dry) before applying with a short, stiff bristle brush or roller. Trowel application is possible if needed. For larger depressions or imperfections (6-10mm), use less liquid for a thicker consistency. Allow each coat to dry before applying additional layers.

Application Information

• Recoatable: 8-12 hours
• Elongation: >42% (air), >31% (under water)
• Tensile Strength: >20 kg/cm²
• VOC Content: 0.5 g/L
• Density: 1850 kg/m³
• Mix Ratio (Powder to Liquid): 3:1 by weight
• Water Penetration (DIN 1048): 1.5 Bar with no leakage
• Potlife:
  • @ 25°C: 2 hours
  • @ 40°C: 30 minutes