Home Breather Membrane Permavent DRY ROOF

Permavent DRY ROOF

Indestructible Breather membrane


For use on all types of domestic and commercial roofing and walling applications, including:
cold non vented
traditional hybrid
cold vented
Scottish and fully boarded applications



The increasing demand of modern construction can lead to conventional breather membranes being overloaded at certain times of the day. The DRYROOF super absorbant fleece is designed to cope with the tidal movement of condensation through the home at different times of the day. DRY ROOF can store high level of condensation at peak times and slowly release it through the day.

Permavent use the very latest technology from the medical industry to encapsulate the highest grade hydrophobic film inside the very highest quality spunbond polypropylene layers. Permavent-DRY ROOF is specially designed to be extremly tough a durable and will maintain its integrity for the duration of the life of the roof. All Permavent membranes offer the best performance in their class with superior strength, breathability, flexibility and durability.

Permavent-DRY ROOF is also fully certified under the CE having been tested and certified by independent European laboratories.

Permavent Membranes are certified for use in all types of roofing and walling applications and conform fully with
BS 5250: 2011 Code of practice for control of condensation in buildings.
BS 5534: 2003 +A1 2010 Code of practice for slating and Tiling.
BS 8000-6: 1990 Workmanship on building sites.
BS EN 1991-1-4; 2005 +A1: 2010 +UK NA.
BS EN 13859: Flexible sheets for Underlays.
BS EN 13501-1 2007.

Permavent-DRY ROOF is an indestructible membrane and is guaranteed to maintain its intergrity for over 40 years.

DRY ROOF will allow for safe working at heights when installed on the roof.

Suitable for all types of roofing and walling construction.


Weight, g/m2 230
Water tightness, class w1
Water vapour transmission (sd),m 0.02
Maximum tensile force (MD), N/50mm 670
Maximum tensile force (CD), N/50mm 520
Elongation at max. tensile force (MD), % 60
Elongation at max. tensile force (CD), % 80
Resistance to tearing MD (nail shank), N 300
Resistance to tearing CD (nail shank), N 360
Roll size:

1m x 50m
12 per pallet

Requirements of BS 5534 annex A for wind uplift


NOTE 1: The figures are based on BRE Digest 489. For greater clarity users are advised to refer to the enlarged version of this document (available on our website).
NOTE 2: Zone suitability applies only for underlays in applications where a well-sealed ceiling is present, ridge height is not greater than 15m, roof pitch is between 12.5° and 75°, site altitude is not greater than 100m and no significant site topography is present. Other applications might require underlays with greater wind uplift resistance and it is advisable to seek professional advice.

Geographical wind zone Design wind pressure, Pu, for underlay (N/m2)
Well sealed ceiling (e.g. standard domestic application) Minimum requirement
5 1600
4 1330
3 1150
2 975
1 820
Not sealed or non-ceiling (e.g. garage or warehouse) 1900
Not sealed or non-ceiling in addition to permanent structural opening (e.g. car port or open store) 2350

Permavent apex wind uplift results

Batten gauge Declared Wind Uplift Resistance,
PD (N/m2)
Zone Suitability
?345 mm
(maximum gauge, large format tiles)
Taped lap: 2748 1 to 5 (All aplications)
Batten restrained lap: 1267 1 to 3 (Domestic aplications)
(600mm slates)
Taped lap: >2500 1 to 5 (All aplications)
Batten restrained lap: >2497 1 to 5 (All aplications)


Following the success of the Queen’s award winning Easy Verge, here at Permavent we are proud to announce the launch of the recently developed Easy VergeTrim. This latest addition to the Easy Roof System has been specially designed to meet the requirements of the Scottish and refurbishment markets.

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