Advanced Multi-Surface Waterproofing Solution
Stop Leaks Before They Start. Protect Your Roofs, Gutters & More.
RCM Leak Block is your go-to, high-performance waterproofing coating designed for long-lasting leak protection on a wide variety of surfaces. From fibre cement roofs and chromadek to Nutec tiles, AluZinc sheeting, and even garden pots, this versatile, water-based solution delivers powerful, durable waterproofing you can trust.
With superior flexibility and advanced adhesion properties, RCM Leak Block ensures cracks, gaps, and vulnerable areas stay sealed-even in coastal conditions. Easy to apply by brush or roller, this product is ideal for DIY homeowners and professionals alike.
Key Features:
Suitable for Multiple Surfaces - Works on fibre cement, Nutec, chromadek, metal, garden pots, and more
Superior Flexibility & Crack Bridging - Perfect for roofs, flashing, and detailing
Ideal for Membrane Applications - Excellent adhesion with reinforcement membranes
Coastal Grade Protection - Third coat recommended for high-exposure environments
Low Odour & Eco-Friendly - Safe, water-based formula
Up to 3-4 Years Maintenance-Free Performance
Perfect For:
- Roofs, flashing, and parapets
- Window sills, garden pots, wall edges
- Nutec sheeting, AluZinc, Chromadek panels
- Garden features needing waterproofing
Application Made Simple:
1 Surface Prep - Clean and dry thoroughly. Remove loose particles, grease, or fungal growth
2 Prime if Required - Use primers on rust-affected or difficult surfaces (e.g., galvanized sheeting, Nutec, asbestos)
3 Apply 2 Coats - By RCM Paint Brush or roller. A third coat is recommended in coastal areas
4 Membrane Use - For added reinforcement on cracks and joints
Dry to Touch: ~2 hours @ 25 C
Maintenance Coat Recommended: Every 3-4 years
Technical Specifications:
- Finish: Matt, smooth
- Coverage: Approx. 6m double coated (0.8-1kg/m depending on surface)
- Pack Sizes: 5L | 6kg | 7.5m (double coated)
- VOC: Low
- Recommended Film Thickness: 1000 microns WFT
- Application Temperature: 10-30 C, RH 85%
In addition, you can add the following to enhance your waterproofing system,
RCM Paint Brush
RCM Waterproofing Membrane
RCM Water Based Plaster Primer
RCM Acid Metal Etch Primer
Safety First:
- Keep out of reach of children
- Avoid eye and prolonged skin contact
- Non-toxic, non-flammable
- Dispose of according to local regulations
Hazard Statement: May cause allergic reaction
What's in the box
1 x RCM Leak Block Waterproofing Coating 20 Litre
