GP®1 Gas Barrier is a multi-layer, low-density polyethylene membrane, reinforced with a polypropylene grid with integral aluminium foil. GP®1 is specifically designed and manufactured to perform as a Methane, Carbon Dioxide, Radon, Ground Gas, air & moisture protection system.

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Product Benefits

  • High quality reinforced membrane.
  • Low permeability to Bulk ground gas, carbon dioxide, methane and radon.
  • Complies with latest codes of practice as published by the BRE and CIRIA, and BS 8485.
Product Description

GP®1 is a high quality proprietary gas resistant damp proof membrane, manufactured from low density reinforced polyethylene (LDPE). This products is ideal for use on sites where ground gas contamination is present.

GP®1 incorporates an aluminium foil core, offering additional protection against Methane and Carbon Dioxide in addition to Radon and Bulk Ground gas. GP®1 can be used on any site where carbon dioxide, methane, bulk ground gas and/or radon is present up to and including BS8485:2015 + A1 2019 Characteristic situation (CS) 6. The barrier is sufficiently resistant to the ingress of harmful gases into a building.

MaterialPolypropylene Aluminium
ShapeRectangular - supplied in roll form.
Size2 x 50 m x 0.6 mm
Warranty60 Year (minimum)
Uniclass 2015Pr_25_57_65
CAWSJ40/35 Loose laid plastics or rubber gas retardant damp proofing
D21/38 Gas-retardant membranes
J40/140 Loose laid plastics or rubber sheet gas retardant damp proofing
J40/145 Loose laid weldable polyethylene gas retardant damp proofing
D21/350 Gas-retardant membrane
Product rangeGas Barriers
MaterialLow-density polyethylene (PE-LD).
PurposeGas Retardance.
StandardTo BS 8485: 2015 + A1 2019.
Performance Characteristics
Tensile Strength480 N/50 mm.
Tear Resistance330 N, 400 N.
Elongation to break20%.
Resistant to underground gasesMethane - 0.09 ml/m2/day atm. Carbon Dioxide - 0.09 ml/m²/day/atm. Radon - 8 x 10(-15).
Third party certificationBritish Board of Agrément (BBA) Certificate. - Certificate No. 12/4912.
CE Mark - EN 13967.
FormPolypropylene reinforcing grid with aluminium foil.
Recycled content0%
CharacteristicsTest MethodUnit
ThicknessEN 1849-20.6mm
Thickness - between ScrimBS EN ISO 9863-1:20160.4mm
WidthEN 1849-2Various (2m minimum)
Length EN 1849-2Various (50m minimum)
WeightEN 1849-2370 G/M2
CharacteristicsTest methodUnit
Water ColumnEN 20811>300
Resistance to Water PenetrationEN 18967, EN 1928PASS
Water TightnessEN 1296, EN 1367, EN 1928PASS
CharacteristicsTest MethodUnit
Resistance to Static LoadEN 12730-B20 Kg
Tensile Strength (MD)EN 12311-1600 N/50mm
Tensile Strength (CMD)EN 12311-1480 N/50mm
Tensile Elongation (MD)EN 12310-120 %
Tensile Elongation (CMD)EN 12310-120 %
Puncture ResistanceEN 122361.25 kN
Resistance to Tearing (Nail Shank) MDEN 12310-1400 N
Resistance to Tearing (Nail Shank) CMDEN 12310-1400 N
CharacteristicsTest MethodUnit
Transmission Rate of Volatile Liquids - DieselISO 6179:2010 (B)0.246 g/m2/h
Transmission Rate of Volatile Liquids - XyleneISO 6179:2010 (B)0.571 g/m2/h
Transmission Rate of Volatile Liquids - TolueneISO 6179:2010 (B)0.583 g/m2/h
Transmission Rate of Volatile Liquids - PetrolISO 6179:2010 (B)0.135 g/m2/h

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.

On more heavily contaminated sites, a passive or active venting system in addition to a gas barrier may be required to dilute the gases 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 should be installed in accordance with the product installation guidelines, and in accordance with BS 8485:2015.


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.

Ground Bearing Slab

Roll weights can be in excess of 20 kg and hence appropriate care and equipment is required for unloading and handling.

Rolls of GP®1 should be stored on stable/level ground and stacked not more than five rolls high, with no other material stacked on top. The rolls can be stored outdoors when packaged, but should be protected from exposure to UV.

CE Mark
CE Mark - EN13967:2012 (A1 2017)
NHBC Standards Compliant
BSI Kitemark
Conforms to BS 8485:2015 + A1 2019
BBA Logo
BBA Certified - Certificate No. 20/5728

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.

Version 1 certified to 2.1

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 related 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

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

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

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


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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