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Cromar Vent 3 Classic: 50m x 1m

by Cromar
Original price £46.20 - Original price £46.20
Original price
£46.20 - £46.20
Current price £46.20
in stock, ready to be shipped

Cromar Vent 3 Classic Breather Membrane

The Cromer Vent 3 Classic membrane is a triple-layer fabric, high-performance membrane. It is layers of spun-bonded polypropylene around a micro-porous polypropylene film. This roll is 50m x 1m and covers 50m ²

It is a highly vapour permeable, and waterproof membrane that is designed for use in either a fully supported or unsupported tile, slate or metal roofing system It has high tensile strength and great wind uplift resistance and conforms to a number of standards including BS 5534:2018 and BS 5250.

Specification Value
Weight, g/m ² 115
Tensile Strength

MD 195N/50mm

TD 130N/50mm


MD 51%

TD 65%

Nail Tear

MD 99N


Hydrostatic Head 281cm
Reaction to Fire Class E
Resistance to Streaming Water Pass
Resistance to Water Penetration W1
Water Vapour Resistance (Sd)(m) 0.02
UV Resistance 3 Months

The outer layer of the membrane acts as a functional waterproof surface, the middle is the breathable waterproof membrane with the inner layer protecting the membrane from damage. It is ideal to use draper over rafters or to laid over insulation.

The membrane is laid horizontally from the eaves with the logo on the outermost working up the roof.

Minimum Horizontal Laps

Roof Pitch Min Horizontal Lap Partially Supported (mm) Min Horizontal Lap Fully Supported (mm) Min Horizontal Lap (mm)
12.5 ° - 15 ° 225 150 100
15 ° + 150 100 100

Cromar is suitable for use across wind zones 1-5 depending on the roof's batten gauge.

Windzone Chart

Batten Gauge 345 mm 245 mm 345mm (Taped Laps) 345 mm (Integral Tape)
Vent 3 Classic Zones 1-2 All Zones All Zones All Zones

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