JUTA GP®1 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

  • High quality reinforced membrane.
  • Low permeability to hydrocarbon and VOC vapours, carbon dioxide, methane and radon.</li
  • Complies with latest codes of practice as published by the BRE, CIRIA and BSI (BS 8485).
Product Description

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

Self adhesive membranes are bituminous membranes, composed of self-adhesive SBS polymer modified bitumen incorporating an upper membrane element, and a lower surface finish of siliconized release film. The type of SAM is dependent on the application scenario as prescribed below, and they are generally used for the gas/waterproofing of underground structures where harmful ground gasses are anticipated, and as a self-adhesive accessory to GP® membrane systems.

GP<sup>®</sup>1 SAM
SBS polymer-modified.
ShapeRectangular - supplied in roll form.
Size0.9 x 20 x 1.2 mm
Warranty Description60 year
Uniclass 2015Pr_25_57_08_08
CAWSJ40/45 Self-adhesive bitumen gas retardant damp proofing/ tanking
J40/40 Self-adhesive bitumen damp proofing/ tanking
J40/190 Self-adhesive bitumen damp proofing/ tanking
J40/180 Self-adhesive bitumen gas retardant damp proofing/ tanking
Product RangeGas Barriers
Standard To BS 8485, BS 8102, CIRIA C735.
Third-party certificationCE certified to EN 13967+ A1.
FormBitumonous gas and water proof sheet.
Carrier material High-density polyethylene (HDPE).
Bitumen modification SBS polymer-modified.
Gas inhibitor Aluminium foil.
Weight (minimum) 1100 g/m2.
Thickness (minimum) 1 mm.
Surface finishes
TopWhite cross laminated high-density polyethylene.
UndersideSiliconized paper release film.
Width (options) 300 mm.
900 mm.
CharacteristicsTest MethodUnit
ThicknessEN 1849-21.2 mm
WidthEN 1849-20.9 or 0.3 m
LengthEN 1849-220 m
WeightEN 1849-21100 g/m2
CharacteristicsTest methodUnit
WatertightnessEN 1928PASS
Water Vapour TransmissionEN 19310.013 g/m2/day
CharacteristicsTest MethodUnit
Tensile Strength (MD/CMD)EN 12311-2 (A)500 N/50mm
Elongation (MD/CMD)EN 12311-2 (A)> 12 %
Resistance to Static LoadEN 1237020 kg
Joint StrengthEN 12317-2> 30 N
Durability and Water Tightness (Ageing and Chemicals) 60 kPaEN 1847Pass
Resistance to Nail Tear (MD/CMD)EN 12310-1> 300 N
Resistance to FireEN 13501F Euro Class
CharacteristicsTest MethodUnit
Methane PermeabilityEN ISO 15105-1< 0.68 ml/m2/day/atm
Carbon Dioxide PermeabilityEN ISO 15105-1< 2.81 ml/m2/day/atm
Radon PermeabilityK124/02/958.0 x 10-15 m2/S

Can be used on any site in accordance with BS8485:2015 and NHBC requirements where carbon dioxide, methane or radon is present up to and including CIRIA 665 SITUATION 6. The barrier is sufficiently resistant to the ingress of harmful gasses into a building. On more heavily contaminated sites a passive or active venting system may be required to dilute the gasses down to acceptable levels and specific design advice should be sought.

JUTA UK – radon, ground gas, vapour, air and moisture barrier characteristic properties:

  • High Chemical Resistance
  • High resistance to Ground Gasses
  • Long Term Durability (Performance guaranteed for the lifetime of the building)
  • Compatible with all building materials
  • Manufactured to meet the most up to date British Standards and guidance.

GP®1 SAM should be installed in accordance with the product installation guidelines, and in accordance with BS 8485:2015, and/or BS 8102:2009. It is recommended that GP®1 SAM is not applied in temperatures below 10oC, in colder weather the material can be warmed slightly to aid adhesion.

GP<sup>®</sup>1 SAM

A selection of standard details for information and education purposes only. Note - it is strongly advised appropriately qualified, and insured personnel undertake gas membrane installs. A gas membrane performs a critical function in the application setting and has an anticipated design service life in excess of 60 years. Do not attempt to install gas membranes from these details alone. Sole rights for use and distribution are owned by JUTA UK LTD.

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

Rolls of GP®1 SAM should be stored on in a cool, dry place, and be protected from exposure to rain, sun, heat and cold temperatures prior to installation. Exposure to sunlight for extended period of time could cause difficulty with removal of the release film.

CE Mark
CE Mark - EN13967:2012 + A1:2017 Type (A/T)
BSI Kitemark
BS 8485:2015 Compliant (Methane and Carbon Dioxide Barrier)
BBA Certificate 22 6076
BBA Certified - Certificate No. 22/6076

BIM objects are digital descriptions of products or materials that, when combined with other BIM objects create a Building Information Model. These downloadable files can be used for these purposes.

Download from NBS National BIM Library
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>1 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>1 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>1 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>1 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
GP®H 0.6mm

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