Home Breather Membrane Permavent MAX ALL ZONES






1 - 5

taped lap

1 - 5

battened lap


list-Suitable for all wind zones regardless of fitting method

list- For use on any types of roofing/walling applications


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. Unlike other companies, who simply stick the different layers together, Permavent membranes are manufactured in a single process that greatly improves the quality and integrity of our membranes. This 3 in 1 process means that Permavent offer the best performing breather membranes in their class with superior strength, breathability, flexibility and durability.

Permavent-MAX 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: 2014 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.


Weight, g/m2 150
Water tightness, class w1
Water vapour transmission (sd),m 0.02
Maximum tensile force (MD), N/50mm 350
Maximum tensile force (CD), N/50mm 240
Elongation at max. tensile force (MD), % 70
Elongation at max. tensile force (CD), % 70
Resistance to tearing MD (nail shank), N 140
Resistance to tearing CD (nail shank), N 230
Roll size:

1m x 50m
24 per pallet

1.5m x 50m
24 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: >2500 1 to 5 (All aplications)
Batten restrained lap: 997 1 to 2 (Domestic aplications)
(600mm slates)
Taped lap: >2500 1 to 5 (All aplications)
Batten restrained lap: >2500 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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