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Universal Vapour Permeable Roof Underlay

170gsm weighted underlay
Integrated tape system for sealing underlay laps
Provides a vapour-permeable underlay system with superb wind-uplift resistance
Unrestricted usage Zones 1-5, and fully compliant with BS 5534.
No need to increase laps to coincide with tile batten courses, minimising cost
No need to use an additional ‘fly’ batten to secure laps
Printed guidance lines
Provides a visual reference to ensure sufficient lap to the British Standard
Ensures that the underlay is laid consistently and straight

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Description

Marley Universal Vapour Permeable underlay is a high-performance, breathable roof membrane for use in a range of pitched roof constructions.

Complete with an integrated tape system, this underlay provides and effective wind barrier with unrestricted usage across all UK wind zones (BS 5534).

Manufactured using a multi-layer bonding process of polypropylene laminates, the underlay is an ultra-strong, durable, and easy-to-install under-tile layer that is suitable for warm or cold roof applications.

Function & Compatibility

Each underlay is manufactured using the latest materials and processes, and each incorporates a number of useful features that assist in ensuring installation that is not only correct, but also compliant with the latest British Standards.

Material	PP 3 layers
Weight	170gsm (-10%+10%)
Resistance to water penetration	W1
Batten gauge	<250 (Zone 1-5) <345 (Zone 1-5)
Adhesive tapes	1
Tests	CE, BBA, IBA approved
Tensile properties
Tensile strength - longitudinal direction (N/50mm)	400 (-80)
Tensile strength - transverse direction (N/50mm)	260 (-50)
Elongation - longitudinal direction (%)	80 (-20)
Elongation - transverse direction (%)	100 (-22)
Resistance to tearing - longitudinal direction (N)	190 (-50)
Resistance to tearing - transverse direction (N)	190 (-60)
Flexibility at low temperature	-60^oC
Resistance to water penetration after artificial ageing	Class W1
Reaction to fire	Class E (When tested to EN11925-2
Tensile properties after artificial ageing
Tensile strength - longitudinal direction (N/50mm)	380 (-80)
Tensile strength - transverse direction (N/50mm)	220 (-50)
Elongation - longitudinal direction (%)	65 (-20)
Elongation - transverse direction (%)	80 (-22)
Water vapour transmission properties (S_d)	0.029 (+/-0.01) m