The Multi surface-One Coat Roofing System
A fast-drying, water-based waterproofing membrane for flat roofs
One-component aliphatic polyurethane. Rain resistant in around 30 minutes, no topcoat, no solvents, applied straight from the tub.
Why roofers use it
Single component, used straight from the tub with no additives.
Can be applied to various substrates, including OSB and plyboard, concrete, GRP, felt, asphalts and metals.
Rain resistant in as little as 30 minutes.
Touch dry in 45–60 minutes.
Low VOCs, and virtually no unpleasant fumes.
Easy to use, one application process.
Tools wash out with water. No requirement for solvents.
Why homeowners choose it
- A long-lasting and reliable roofing system
- No hot works
- No strong smells
- Suitable over various substrates, applied as part of either a 20 or 25 year system depending on the build-up used.
Technical reasons why installers choose Permaflex PU-Fast
Reduced risk of pinholingMany solvent-based, moisture-curing PU-1K coatings are prone to foaming, blistering and pinholing, especially in hot or humid conditions, caused by the reaction between isocyanates and moisture generating CO₂ during cure. Permaflex PU-Fast cures through normal water evaporation instead, so it's far less exposed to that problem. |
Colour stability and UV resistanceAliphatic polyurethane holds its colour under UV exposure and resists yellowing and chalking, without needing a separate topcoat. Passes accelerated UV ageing testing to ASTM G154, over 1,000 hours. |
Compatibility with existing coatings and membranesSuitable over GRP, existing liquid membranes, bitumen and single-ply membranes. |
Water vapour permeabilityWater vapour permeability rated Class II to EN ISO 7783. |
Low VOCVOC content of the ready-to-use product is under 40g/l, within the EU Directive 2004/42/CE limit for this product category. |
Early rain resistanceRain resistant within 30 minutes of application at +23°C. |
Fast curingTouch dry in 45–60 minutes at +23°C, recoat in 2 hours at the same temperature. Times extend in cold or humid conditions and shorten in heat. |
Simple applicationNo additives, single application, tools clean up with water immediately after use. |
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Other Benefits
- One application process
- Can be applied to damp surfaces (not wet)
- Suitable for walkable areas
- Resistant to ponding water
- Impact and tear resistant
- Flexibility of 350% elongation
- 20+ year service life
Technical figures
| Property | Figure |
|---|---|
| Touch dry | 45–60 minutes at +23°C |
| Rain resistance | approx. 30 minutes |
| Coverage | approx. 7–8m² per 13kg tub, substrate dependent |
| Pack sizes | 4kg and 13kg pails |
| Colour | Graphite grey |
| Clean-up | Water, immediately after application |