LEAKSEAL®
CEMLASTIC
A polymer-modified, fibre-reinforced flexible cementitious waterproofing slurry designed to provide excellent tensile strength, crack-bridging and long-term protection on concrete, masonry and brickwork in both exposed and immersion conditions.
LEAKSEAL® CemLastic is a two-component, polymer-modified flexible cementitious waterproofing slurry reinforced with fibres to deliver an optimal balance between tensile strength and elongation. The system forms a durable, crack-bridging and waterproof coating suitable for use on cementitious substrates, plastered surfaces, brickwork and blockwork, performing reliably under both positive and negative water pressure.
Features & Benefits
- Fast-Drying, Self-Priming System – Easy application and reduced installation time.
- Positive & Negative Water Pressure Resistance – Suitable for internal and external waterproofing, including below-grade structures.
- Resists Water Pressure up to ~5 bar – Suitable for immersion and structural waterproofing applications.
- Highly Flexible, Crack-Bridging up to ± 1.2 mm – Maintains performance even at very low temperatures (≈ −20°C).
- Excellent Adhesion & Tensile Strength – Bonds strongly to concrete, masonry and cementitious substrates.
- Non-Corrosive & Anti-Carbonation Protection – Helps protect reinforced concrete from CO₂ ingress and deterioration.
- Oil-Resistant & Chemical-Resistant – Suitable for environments exposed to salts, sulphates and marine conditions.
- Non-Toxic When Fully Cured – Safe for fishponds and potable-water applications (WRAS compliant).
- Over-Coatable – Compatible with acrylic, polyurethane and polyurea topcoats.
- Renders Leaking Surfaces Waterproof in Two Applications – Practical solution for refurbishment and repair projects.
Intended Uses
LEAKSEAL® CemLastic is designed for structural and surface waterproofing across civil, residential, commercial and marine-exposed environments.
It is suitable for applications ranging from under-tile waterproofing and wet areas to water-retaining structures, roofs, marine-exposed environments and structural protection projects. CemLastic can be applied to damp substrates, bonds well to existing coverings, and is compatible with ceramic, mosaic and natural-stone finishes. It provides long-term durability even in coastal, industrial and harsh climatic environments.
Can be applied to damp surfaces and over existing ceramic, mosaic or stone coverings where properly prepared.
Typical applications include:
- Under-tile waterproofing — showers, balconies, terraces, swimming pools
- Flat concrete roofs and gutters
- Fishponds, dams, reservoirs, canals and concrete piping
- Basements, tunnels and below-grade walls
- Interior and exterior wall damp-proofing — positive & negative pressure
- Retaining walls and foundation walls buried in ground contact
- Marine and chemical-exposed structures — seawater, salts, sulphates
- Crack sealing of non-moving hairline cracks in concrete
- Protective anti-carbonation coating for concrete structures
- Lightweight blocks, plasterboard, marine-grade plywood and masonry substrates
