JUTA GP®SAM gas protection self-adhesive membrane is a bituminous gas-proof and waterproof sheet. It is used for the gas/ waterproofing of underground structures where harmful ground gases are anticipated and as a self-adhesive accessory to GP®1.

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Product Benefits

  • Complies with latest codes of practice as published by the BRE, CIRIA and BSI (BS 8485:2015
Product Description

JUTA GP®SAM is composed of self-adhesive SBS polymer-modified bitumen incorporating GP®1 with an upper surface finish of Black reinforced LDPE, and a lower surface finish of siliconized release film.


Roll weights can be in excess of 20kg (approx. 33kg / roll) and hence appropriate care and equipment are required for unloading and handling. This product is non-toxic nor flammable.


Rolls of JUTA GP®1 SAM should be stored horizontally, and pallets should not be stacked on top of one another. It should be stored in a cool, dry place and be protected from exposure of rain, sun, heat and cold temperatures prior to installation. Exposure to sunlight for an extended period of time could cause difficulty with the removal of the release film.



Take a look at the physical properties of our GP® SAM here. For full product information please see the datasheet linked below.

View Data Sheet
Width0.3 or 1 m
Length20 m
Weight1100 g/m2
Water Vapour Transmission Rate0.013 g/m2/ day
Full InformationCheck out the full data sheet above


JUTA GP®1 SAM should be installed in accordance with the product installation guidelines and in accordance with BS 8485:2015. It is recommended that JUTA GP®1 SAM is not applied in temperature below 10°C in colder weather the material can be warmed slightly to aid adhesion.


Site Investigation
Site Investigation
Site Investigation Reports Monitoring Results. We review these reports and advise routes for compliance.
System Design
System Design
Full Ground Gas Protection System Design available.
Wide library of standard details with site specific details on request.
All our installers are certified NVQ Level 2 qualified installation contractors.
We ensure your project complies with the relevant building regulations.

Ground Gas Standards 

There are many different standards and guidance documents that detail how to understand the risk of ground contamination, and design solutions to mitigate these risks. The different documents relate to different ground contamination. Below are some of the key documents to be aware of and refer to:

BS 8485:2015+A1:2019 – Codes of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings.

  • Ground gases typically found near landfill sites, but can occur from other sources
  • Encourages the use of qualified installers
  • Validation to Ciria C735 is a requirement
  • Additional influences on the system should be considered, such as the hydrostatic conditions, and the likelihood of the source contaminant being in direct contact with the protective measures proposed
GP<sup>®</sup> SAM

BRE 211:2015 – Guidance on protective measures for new buildings. (RADON)

  • Naturally occurring ground gas. Larger concentrations in the South-West of UK
  • Minimum recommendation is a membrane of 300 micrometre (1200 gauge) polyethylene sheet or equivalent
  • It must be installed with considerable care and protected once installed
  • Taped laps are required
GP<sup>®</sup> SAM

CIRIA C748:2014 – Guidance on the use of plastic membranes as VOC vapour barriers

CIRIA C682:2009 – VOC Handbook

  • Risk based approach
  • No quantifiable limits on material performance
  • Testing to ISO 15105-2 and EN 14414/EN 14415
  • 9 main VOC types are tested for
  • Welded laps are required as most tapes are made from bitumen/butyl and are affected by VOCs
GP<sup>®</sup> SAM

CIRIA C735:2014 – Good practice on testing and verification of protection systems to buildings from hazardous gases

  • Good practice on testing and verification of protection systems to buildings from hazardous gases
  • Check design and detailing is in accordance with site requirements
  • Checks the competency of the installer (NVQ LEVEL 2 minimum)
  • Test integrity of the membrane/barrier system
  • Visual inspection
  • Written report on inspection/testing and sign-off

BS8102:2009 – Code of practice for protection of below ground structures against water from the ground

GP<sup>®</sup> SAM

JUTA Solutions & Applications

Our gas protection membranes suit a variety of applications and situations, with our TITAN® range offering not only gas protection but also having superior waterproofing and invasive weed control qualities.

BRE 211 NHBC (Amber 1) BS8485:2015 + A1 2019 / NHBC (Amber 2) C748 C748 BS8102:2009 RPS178 C753 BBA Agreement Certificate
Radon Bulk Ground Gasses Cardbon Dioxide and Methane VOC Vapour Permeation Hydrocarbons Immersions TYPE-A Bonded Waterproofing Invasive Weed Control SuDs Impermeable Membrane
GHDPE 0.6mm

Get In Touch With The Experts

If you feel first class service, premium products direct from source, and bespoke solutions are right for you then don't hesitate to contact our team today on 01772 754177 or email us at info@juta.co.uk

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