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A flexible, loose-laid gas barrier for use on sites with radon, carbon dioxide and methane ground gas. Protects against the ingress of hydrocarbon vapours where it is separated from the ground, e.g. above a block and beam floor.

The barrier incorporates a two-layer low density polyethylene membrane with a polypropylene reinforcement grid and an aluminium foil core. Extremely flexible for ease of installation and robust to cope with site conditions.


  • Gas-proof against radon, carbon dioxide, methane and other contaminants.
  • Protects against damp, acting as a damp-proof membrane (DPM).
  • Can be laid on sand blinding, Delta Protech Geotextile Protection fleece or a smooth concrete finish.
  • Can be patch-repaired.
  • Laps can be joined together either by using a 50 mm Delta Gas Barrier butyl tape or welding by on-site contractors.
  • CE-marked and BBA-certified.

Standard product features

Roll length:

50 m.

Roll width:

2 m.


0.6 mm.


Blue/ grey.

Technical characteristics:

  • Maximum tensile strength, machine direction (MD): 600 N/ 50 mm.
  • Maximum tensile strength, cross direction (CD): 480 N/ 50 mm.
  • Elongation at break MD: 20.
  • Elongation at break CD: 20.
  • Nail Tear Resistance MD: 330.
  • Nail Tear Resistance CD: 400.
  • Radon permeability: 8.0 x 10–15 m²·s–1.
  • Methane permeability (to BS EN ISO 15105-1): <0.09 ml/m²/day/atm.
  • Carbon dioxide (to BS EN ISO 15105-1): <0.09 ml/m²/day/atm.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-65-50/325 Plastics sheets

Product specification

An important note about specifying



Delta Membrane Systems Ltd


+44 (0)1992 523523

Product reference

Delta Memtech M1

Manufacturer details

Delta House,
Merlin Way,
North Weald,
Essex, CM16 6HR
Tel +44 (0)1992 523523
Fax +44 (0)1992 523250
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