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An SBS (Styrene Butadiene Styrene) modified metal lined membrane, designed to prevent water vapour from entering the roof system and causing condensation.

Features and benefits:

  • The membrane has a high percentage of SBS rubber, high-strength fibre-glass reinforcement and monolithic aluminium foil throughout.
  • The aluminium foil placed within the membrane offers a high level of vapour blocking, and therefore condensation building up in the roofing system.
  • The membrane is reinforced with a high-strength fibreglass scrim. The strength provided by the reinforcement resists movement and has good dimensional stability.
  • When the SBS rubber is properly dispersed throughout the high penetration asphalt, the rubber provides increased thermal shock resistance, UV protection, heat resistance, elongation, and low temperature flexibility. To ensure proper dispersion, a special high shear mixer is used in manufacturing.


The membrane is used as a vapour control layer (VCL) for any of Garlands torch-applied or self-adhesive membranes to prevent water vapour from entering the roof system. It is fully compatible with SBS modified membranes. For lower side finishing with adhesive polymers: Cold applied. Consult manufacturer for details.

Standard product features


  • Reinforcement type: High strength fibre-glass.
  • Compound type: Bitumen modified with thermoplastic rubber (SBS).
  • Surface finishing: Upper side: Textured polypropylene film. Lower side: Adhesive compound.

Technical characteristics:

  • Size (to EN 1848–1, l x w): 10 x 1 m.
  • Thickness (to EN 1848–1): 3 mm.
  • Weight (to EN 1849–1): 4 kg/m².
  • Watertightness (to EN 1928:2000 Method B): Pass, 60 kPa.
  • Reaction to fire (to EN 13501-1): Euroclass F.
  • Maximum tensile force (to EN 12311-1): 1200/ 1200 N/50 m.
  • Elongation (to EN 12311-1): 4/ 4%.
  • Resistance to tearing (nail shank) (to EN 12310-1): 200/ 200 N.
  • Flexibility at low temperature (to EN 1109) -20°C.
  • Flow resistance at elevated temperature (to EN 1110): 100°C.
  • Softening point of bitumen (to ASTM D36): 130°C.
  • Water vapour transmission properties (to EN 1931) 1 500 000 μ.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-65-50/363 Polymeric membranes
45-65-50/325 Plastics sheets

Product specification

An important note about specifying



Garland UK


+44 (0)1174 401050

Product reference

SA Flex Vapour Barrier

Manufacturer details

The Garland Company UK Ltd,
Second Way,
Bristol, BS11 8DF
Tel +44 (0)1174 401050
Fax +44 (0)1174 401057
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