GP® LIQUID BARRIER is a multi-use synthetic rubber-based gas-proofing and waterproofing system. It can be specified as a liquid gas proof barrier, a damp/waterproof membrane or both dependent on the project requirement. The product is an elastic, UV-resistant, single component system supplied in red.

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Product Benefits

  • Rapid drying
  • Methane and Carbon Dioxide barrier
  • Dual-use Damp/Waterproof and gas barrier
  • Damp surface tolerant
  • Non-toxic
  • Excellent bonding strength to common construction substates
  • Good crack-bridging properties
  • Resistant to weak mineral acids
  • Good Alkali and brine solution resistance.
Product Description

GP® LIQUID BARRIER is a multi-use synthetic rubber-based gas-proofing and waterproofing system. It can be specified as a liquid gas proof barrier, a damp/waterproof membrane or both dependent on the project requirement. The product is an elastic, UV-resistant, single component system supplied in red. GP® LIQUID BARRIER is a water-based non-hazardous product, safe and easy to apply direct from the packaging using a roller, brush or airless spray. The product can be applied to dry or damp substrates and dries in approximately one hour to form a tough semi-gloss finish.


  • Methane, Carbon Dioxide and hydrocarbon vapour suppression
  • Seamless liquid-based gas proofing solution
  • Waterproofing and gas suppression at ground floor level, basements and subterranean structures
  • Tanking applications, retaining walls etc.
  • Bunding applications (please verify chemical resistance prior to specification)
  • Can be applied under tiled areas for secondary protection in wet areas
  • Repairs of floor surfaces; can be applied as a base coat on a damaged surface before application of a self-levelling thin section screed (compatible with latex or cementitious)
  • Concrete roof protection
  • Silage and sewage tank lining
  • Barrier to water vapour for brickwork, blockwork and stonework.
Characteristics Specification
Density1.5-1.6 g/cm3 at 20˚C
Form SuppliedViscous liquid
Pack Size8 kg / 15 kg (Bespoke sizes available on request)
Shelf Life 18 months (unopened)
OdourLatex (Vanilla)
Drying Time 1 hour at 20˚C
Characteristics Test MethodSpecification
Water Vapour Permeability <0.5 g/m2/day
Methane permeability EN ISO 15105-1<28.8 ml/m2/day/atm (ISO 15105-1)
Carbon Dioxide permeability EN ISO 15105-1 <267 ml/m2/day/atm (ISO 15105-1)
Radon PermeabilityK124/02/959.5 x 10-12 m2/s
CharacteristicsTest MethodUnit
Water tightnessEN 1928PASS – watertight at 0.6mm thick
*Permeability values based on min. 0.6mm thick.
Characteristics Test MethodSpecification
Adhesion to concrete> 1.1 N/mm2
Static Crack Bridging AbilityBS EN 1062-7 - ACLASS A5 (> 2.5mm)
Dynamic Crack Bridging AbilityBS EN 1062-7 - B4.2No failure - 0.5mm - 20,000 cycles
Chemical ResistanceBS EN 13529:2003 Resistant to a range of chemicals
Elongation ASTM D2370ASTM D2370> 100%
Dry Film Thickness (DFT) 600-1000 µm (2-coats) 600µm - brush/roller application 1000µm - airless spray application

All surfaces should be smooth, clean, dry, sound and free from frost, oil, grease, condensation and other contamination. Remove any organic growth with a fungicidal wash as may be necessary.

Non-structural cracks, less than 0.5mm, must be filled. Structural cracks must be first repaired and filled. Fill holes and re-point flush to the finish using a cementitious repair mortar.

Newly laid concrete should have a clean textured surface, internal angles should be filleted with a 45° fillet using a suitable cementitious mortar.

For expansion joints, ensure that the product is applied well into the rebate before the expansion media is applied. Other gas membranes must be exposed and lapped with where present.

The minimum ambient temperature for application is 5°C, it is not recommended to apply the product at temperatures below this as specified drying times will not be achieved.

No priming is necessary with this product. To assure that the product fully wets out the substrate the surface may be dampened. There should not be any standing water or soaking.

Product is recommended to be brush, roller or airless spray applied, avoid pouring directly onto a horizontal surface. This may cause puddling during application and increase drying time. Stir the product well for 2 minutes before use.

Should the product require thinning, it is recommended to thin 5% by volume of water initially and evaluate the resulting viscosity. The product should not need to be thinned in normal conditions of storage and use.


For a dry film thickness of 0.6mm then apply at 0.85kg/m2 per coat (1.7kg/m2 per 2-coat system). For the application of a dry film thickness of >0.3mm in a single coat it is recommended that the membrane is applied by airless spray. Using airless spray, a single application dry coat thickness up to 1mm may be attained.

The product can be applied as a single coat in certain applications but two coats is universally recommended. Recommended coating thickness is 300µm (0.3mm) per coat and 600µm (0.6mm) for the overall membrane thickness for best performance. Thicker applied coatings will require greater drying time. Performance is improved where the second coat is applied at right angles to the first but it is not essential to do so. Leave 90 -120 minutes before overcoating with the second coat, a touch dry test on the first coat will indicate readiness. It is recommended that the second coat is applied within 24 hours of the first coat. Full cure of the membrane is 48 hours after the second coat application.

Concrete roofing applications:

Blistering may occur if application is not undertaken as recommended. Blistering results from heat from the sun causing a vapour pressure build below the membrane. This is more likely to occur if the concrete surface is wet so it is recommended for this particular application that the substrate is dry. Ensuring a good bond to the substrate is essential; vigorously brush the first coat into the concrete using a stiff bristled broom. So far as possible avoid application of the membrane on a day with strong, direct sunlight (overcast but dry is ideal). To enhance bonding it may be necessary to prime the roof with a slurry of screeding latex and cement if the original surface condition is poor.


It is always advisable to check product compatibility and adhesion by testing on a sample area before starting any sizeable project.
Do not apply if rain is forecast before product can fully dry.

Exercise caution on coating thickness, exceeding recommended coverage rates increases probability of cracking and splitting.

Do not apply this product over bituminous surfaces.

Spray: For further application information please consult the Technical Department.

For cleaning tools use water immediately after use.


All components are REACH (Reg. (EC) No 1907/2006) registered. The product does not contain any Substances of Very High Concern (SVHC).

When designing Type A structures (as classified in BS 8102: 2009), the product, applied correctly, is capable of providing the levels of protection required for Grades 1, 2 & 3 basements.


Product is not classified as hazardous according to the CLP Regulation (Reg. (EC) No 1272/2008). Refer to the Product Safety Data Sheet for specific information.


Store in cool, dry conditions in the original manufacturer packaging. The product has a 18-month shelf life provided the container is unopened. If opened the product should be used within 1 month and sealed air-tight between uses. Longer storage times may result in fillers falling to the base of the container, rigorous and thorough stirring is recommended prior to application.

CE Mark
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

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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