Permavent APeX





1 - 5

taped lap

1 - 3

battened lap


list-Air and Vapour permeable

list-Integrated Tape (25% less membrane usage)

list-Use without additional ventilation

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


Following years of development, Permavent have further increased the bound aries of breather membrane technology to produce a super high performance Vapour Permeable Underlay (VPU) that complements our impressive range a high performance Roof Tile Underlays (RTU's).

The unique induction bonding process allows for stepped changes that increase the flexibility of the boundaries when establishing the final performance of the membrane. We have fine-tuned this technology to produce a breather membrane with Air Permeable qualities that are ideally suited to the construction methods here in the UK.

Permavent APeX was rigorously tested by the BRE where the high performance properties not only achieved superb Air Permeability results but it also passed the BS 5534 annex A test for wind uplift in all regions throughout the UK when installed correctly.

Permavent APeX not only allows vapour to be released from the roof space but because a controlled amount of air is allowed to pass through it there is no need to use additional high level ventilation in many new build applications.

Permavent APeX complies with NHBC requirements for cold roof constructions without the need for any additional ventilation under the NHBC warranty.


Weight, g/m2 180
Water tightness, class w1
Water vapour transmission (sd),m 0.01
Maximum tensile force (MD), N/50mm 358
Maximum tensile force (CD), N/50mm 304
Elongation at max. tensile force (MD), % 70
Elongation at max. tensile force (CD), % 72
Resistance to tearing MD (nail shank), N 214
Resistance to tearing CD (nail shank), N 218
Roll size:

1m x 50m
24 per pallet


1m 50m untaped
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: 2351 1 to 5 (All aplications)
Batten restrained lap: 1177 1 to 3 (Domestic applications)


(600mm slates)
Taped lap: N/A 1 to 5 (All aplications)
Batten restrained lap: 2745 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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