FIBRANskin VENT | Breathable membrane for pitched tiled roofs

FIBRANskin VENT is a breathable waterproofing membrane manufactured in accordance with EN 13859-1:2010 and EN 13859-2:2010 — meaning it covers both roofs and vertical elements. It is installed on the cold side, over the thermal insulation, on ventilated pitched tiled roofs and façades. Water vapour diffusion resistance Sd = 0.03 m, watertightness class W1 with a water column of 2 m. Its key strength lies in its mechanical properties: nail tear resistance of 90 N (MD) / 80 N (XD) and retention of 90 per cent of tensile strength following artificial UV and heat ageing. Practically airtight, with an air permeability of ≤0.1 m³/(m²·h·50 Pa). Mass 82 g/m², operating range -40 °C to +100 °C, roll 1.50 × 50 m (75 m²). 25-year manufacturer’s warranty.

Why nail resistance is the right criterion. A roof membrane does not fail under tension — nobody is pulling on it. It fails at the points of penetration: where the nail or staple has pierced it and the wind, with every gust, exerts a load around the hole. With a strength of 41 N, a roof with dense fastening in a wind-exposed location is clearly more vulnerable than one with 90 N.

The correct question to ask the specifier is not ‘which is better’ but ‘does the project require a B-s1,d0 classification?’

Yes → FIRE SHIELD, with a mineral fibre backing (the classification applies only there).

No → VENT. Mechanically superior, more airtight, more resistant to ageing, more cost-effective.

And a note on airtightness: the figure of ≤0.1 m³/(m²·h·50Pa) is not just a figure of speech. In buildings aiming for low energy consumption or undergoing a blower-door test, the building envelope is judged precisely on this figure — and the difference from ≤2 is an order of magnitude.