Waterproof Paint — Liquid Rubber for Wet Areas
Waterproof paint for exterior use — the term covers a wide range of products with very different real-world performance. Truly waterproof paint forms a continuous seal that wind-driven rain and surface water cannot penetrate, while remaining breathable so substrate moisture can escape outward. Liquid rubber meets both criteria simultaneously, which is why it outperforms cheap waterproofing paints on real outdoor surfaces.
What waterproof actually means
European standard EN 1062-1 classifies water permeability of paint films from W1 (high — not really waterproof) to W3 (low — true waterproofing). RubberPaint Universal achieves W3, the most stringent class. In numbers: less than 0.1 kg/m²·h⁰·⁵ — practically watertight against driving rain.
Equally important: the cured film is breathable in the V2 class per EN 1062-1. Water vapour escapes outward at 60–70 g/m²·day. The combination matters because:
- Closed waterproof paint (W3 + V0) traps moisture inside the substrate — it dries from outside but accumulates inside, eventually causing the film to lift
- Truly waterproof + breathable (W3 + V2) holds rain out but lets residual substrate moisture dry outward — the substrate stays in good condition for years
Where waterproof paint is essential
- Exterior masonry walls — render, brick, blockwork exposed to driving rain
- Plinths and base walls — splash water zone, the lower 1.5 m of every house
- Garden walls and retaining walls — exposed to ground water from behind, rain from front
- Concrete elements — stairs, walls, exposed structural concrete
- Wet rooms inside — bathroom walls (above tile zone), basement walls
- Balconies and terraces — protect underlying screed from water ingress
Comparison with traditional waterproof paint
| Property | Liquid rubber | Traditional masonry paint |
|---|---|---|
| Water permeability | W3 (very low) | W2–W3 |
| Vapour breathability | V2 (open) | Often V0–V1 (closed) |
| Crack-bridging | Yes — elastic membrane | No — rigid film |
| Repairability after years | Single refresh coat | Strip-and-recoat |
Application essentials
Two cold-applied coats at 100–200 g/m² per coat give the full waterproofing performance. First coat soaks into the substrate (extra material on porous concrete or rough render); second coat builds the final film thickness. Rain-fast after 24 hours, full cure 28 days.
For specific applications by substrate see the dedicated Application pages, especially Façade waterproofing, Basement waterproofing and Balcony waterproofing.