Reinforced Polythene Building Membranes
Heavy duty gas barrier DPM
Radon & Methane barrier
Accreditation : BRE 040/97

Grade 871 is suitable for use as a radon and methane barrier, and as a damp-proof membrane in floor constructions. It can be installed over or under concrete ground floor slabs with or without insulation.It can also be used for remedial work and with timber or concrete suspended floors.

Construction

Grade 871 is a multilayer composite membrane with polythene for toughness and water resistance, a multifilament polyester reinforcement for high tear resistance and an aluminium foil core for outstanding barrier performance. Grade 871 is mid-green one side and silver reflective on the reverse side.

Technical Data

Basis Weight (g/m2)		344 g
Tensile Strength	-MD	9.1 kN/m
	-CD	8,9 kN/m
Nail Tear Resistance	-MD	160 N
	-CD	160 N
MVTR		less than 0.01 g/m2/d
Vapour Resistance		>20,600 MNs/g
Radon permeability		2.3(10-12m2s-1)
Improvement factor		approx 500
Methane permeability		less than 0.001 cc/m2/day

Fixing/Sitework

Store rolls on sides under cover until needed. Cover entire site with membrane, overlapping joints 100mm and sealing with a suitable butyl double-sided adhesive tape. Seal around all services through the membrane with a suitable flashing tape, or use "top hat" seals. Carry edges of membrane under DPC of external walls. Repair or replace any damaged areas before covering with concrete.

Please note: the performance of the radon/methane barrier will only be effective if the membrane is effectively gas-tight. Inadequate seams and poorly sealed service entries will allow radon/methane into the completed building.

Availability

Standard Roll Size	2000mm x 50m
Roll Weight	35kg

All information given in good faith and is believed to be accurate. Technical data is based on laboratory testing and represents average values. Specific lots may vary above or below these values.