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A tough, durable self-adhesive membrane specially developed to protect against the ingress of methane and radon gases and other ground gases and contaminants. This is achieved by using aluminium as the primary barrier and reinforcing and protecting this by laminating a tough, biaxially oriented HDPE film to one side and a robust bitumen rubber compound to the other. To facilitate easier lap seals, the membrane has a selvedge of bitumen rubber.

It is used to provide an effective barrier to water, water vapour, radon, methane and carbon dioxidein all forms of construction. When installed and applied correctly, it provides an effective barrier to ground gases in accordance with BS 8485 and provides Type A barrier protection in accordance with BS 8102 – Table 1 and provides levels of protection for grades 1, 2 and 3 in accordance with BS 8102 – Table 2. Under normal conditions of use, Triton TWS/EX 100 GM will provide an effective barrier to water, water vapour, radon, methane and carbon dioxide for the life of the building.

Features and benefits:

  • Low methane gas permeability.
  • Impervious to radon gas.
  • High puncture resistant film.
  • Highly efficient waterproof membrane.
  • Multi-layer laminate to optimize long term protection.
  • Adhesive selvedge to aid effective joint sealing.
  • Self-adhesive.
  • Cold applied.
  • Factory controlled thickness.

General information
Specification data
Product Reference

Triton TWS/EX 100 GM

Standard product features


1 mm.

Roll size (w x l):

1.05 x 28.6 m.


0.1 mm thick aluminium polythene laminate.

Technical properties:

  • Weight: 1.1 kg/m².
  • Puncture resistance (to ASTM E154): 250 N.
  • Elongation (to ASTM D1000): 40%.
  • Membrane strength (to ASTM D1000): 3 N/mm.
  • Peel strength (to ASTM D1000): 2 N/mm.
  • Water vapour transmission (to ASTM E96): <0.1 g/m²/day.
  • Methane gas permeability: <0.03 ml/m²/day.
  • Radon diffusion: 5.0 x 10^-14 m²/s.

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