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Ground Gas Protection

The A. Proctor Group has been in the Gas Protection market for the past 15 years promoting a range of gas membranes and venting components for use on contaminated land sites. Adequate protection against the ingress of ground gas and vapours is crucial and the A. Proctor Group can provide safe, cost effective and value engineered solutions.

Our technical services include CAD details and project specific recommendations utilising the latest guidance and in full compliance with current legislation and standards.


Ground Gas Protection Brochure

Our new & updated Ground Gas Protection Brochure is now available. Download it for complete information on our range of Protech and Provoid Ground Gas products and accessories.Download Brochure

Installation Guides
Material Properties
BIM Objects
UK Availability
CAD Details
Global Availability

Material Properties

Protech GM Super

Property Test Method Result
Roll Length 50 m
Width 2 m
Weight 0.37 kg/m2
Thickness 0.4 mm
Colour Green/Silver
Methane Permeability ISO 15105-1 ≤ 0.1 (ml/day/m2)


Property Test Method Result
Roll Length 50 m
Width 900 mm
Thickness 25 mm
Tensile Strength EN ISO 10319 18 kN/m
Gas Flow Capacity 0.07 m3/s
Compressive Strength 300 kN/m2

Protech VOC Flex

Property Test Method Result
Roll Size - 50 x 2 m
Thickness - 0.55 mm
Weight ISO 536 564 gsm
Tensile Strength EN 12311-1 MD 700 / CD 640 N/50mm
Elongation EN 12311-1 MD 30% CD 25%
Nail Tear Resistance EN 12311-1 MD 500 / CD 540 N
Methane Permeability ISO 15105-1 ≤0.1 ml/m2/day
Determination of Chemical Resistance EN 14414 Methods A-D Pass - No visual degradation
Resistance to Naphthalene ISO 15105-2 (EN 14414 Method C) Pass
Resistance to Benzene ISO 15105-2 (EN 14414 Method C) Pass
Resistance to Toluene ISO 15105-2 (EN 14414 Method C) Pass
Resistance to Hexane ISO 15105-2 (EN 14414 Method C) Pass

Protech Radon 400

Property Test Method Result
Roll size 2 x 50 m
Thickness EN 1849-2 0.43 mm
Weight EN 1849-2 400 g/m2
Sd value EN 1931 290 m
Resistance to static loading EN 12730 method B 20 kg
Water tightness EN 1928:2000, Method A (2kPa Pressure) W1
Against heat ageing (EN 1296) EN 1928:2000, Method A (2kPa Pressure) W1
Against chemicals (EN 1847) EN 1928:2000, Method A (2kPa Pressure) W1
Tearing strength - MD EN 12310-1, mod with EN 13859-1:2010 Annex B 320 N
Tearing strength - CD EN 12310-1, mod with EN 13859-1:2010 Annex B 330 N
Tensile strength - MD EN 12311-1, mod with EN 13859-1:2010 Annex A 385 N/50 mm
Tensile strength - CD EN 12311-1, mod with EN 13859-1:2010 Annex A 295 N/50 mm
Elongation - MD EN 12311-1, mod with EN 13859-1:2010 Annex A 20 %
Elongation - CD EN 12311-1, mod with EN 13859-1:2010 Annex A 17 %
Foldability at low temperature EN 495-5 Pass -45 °C
Radon transmittance SP method 1.4.10-8 m/s
Radon permeability SP method 6.0.10-12 m2/s

BIM Objects

File Format
Provoid - BIM Object - Raft Slab With Membrane Under Slab IFC
Provoid - BIM Object - Suspended Slab With Membrane Under Slab IFC

UK Availability

North East Scotland & Islands
Linda Kay
Regional Sales Manager


South London & South East
Josephine Matchette
Regional Sales Manager


Wales & South West
Marc Blackie
Technical / Regional Sales Manager

07968215 755

North London & East England
Ben Cremer
Technical / Regional Sales Manager


Head Office
The Haugh

Kieran Basi
Regional Sales Manager


Anthony Ruth
Regional Sales Manager

Global Availability

North America
Jeff Dibdin
International Account Manager.


South America
Jeff Dibdin
International Account Manager.


Jeff Dibdin
International Account Manager.


Jeff Dibdin
International Account Manager.


Jeff Dibdin
International Account Manager.


Jeff Dibdin
International Account Manager.



CAD Detail Review

Use this service to check that your proposed detailing is correct. Upload your details, and a member of our technical support team will review and comment on them, offering amendments where required. Click below to get started.

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Book A Zoom Meeting

Our team are available to take Zoom meetings at a date & time that suits you. We are happy to discuss project specific questions, review drawings, assist with specifications, documentation, calculations or anything else you need.

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Contact Us

If you can't find what you're looking for, or have any questions - please feel free to get in contact with a Regional Sales Manager or a member of our sales or technical support team.

Get in Touch

Contact Us

Mathew Spiller

National Technical Sales Manager Ground Gas Protection

07817 872 681


John Johnston

Sales Director

07836 751 128


  • Ground Gas Protection FAQs

    • How do I select the correct membrane for my site?

      The main considerations for choosing the correct gas membrane are the range of gases present on site and the volume flow rate of those gases. As long as a site investigation or ground gas monitoring has been carried out, we are able to determine the level of risk in accordance with BS 8485 for carbon dioxide and methane gases, and BR 211 for radon. The type of membrane installed is also heavily influenced by the level of hydrocarbon contamination in the ground, such as on brownfield sites, which would require a higher level of protection and VOC resistance. Our range includes gas membranes appropriate for all situations and we recommend sending the relevant site information to our technical team for the correct specification and installation instructions.

    • Can anyone install a gas membrane?

      CIRIA C735, the good practice document on verification of gas protection systems, recommends installers should be experienced and qualified to NVQ Level 2 Gas Membrane Installation as a minimum. It is not a requirement for all operatives on site to hold this qualification but installations carried out by others would require a more onerous and intensive verification process to prove it is fit for purpose.

    • Do I still need a separate Damp Proof Membrane in the ground floor?

      Our gas membranes are water resistant and airtight by the nature of their design and they can act as a replacement for the floor DPM in most situations. Depending on the floor construction, it might still be preferrable to utilise both membranes in the assembly. For example, where the gas membrane is installed below the insulation and floor slab, laying a separate a DPM above the insulation will act as a separating layer when the slab is being poured.

    • How do you deal with service penetrations coming through the floor?

      Some penetrations through the floor assembly are unavoidable and it is a case of sealing around them as effectively as possible. We manufacture a variety of accessories to deal with these penetrations such as gas resistant Top Hats, foil-faced bitumen tapes, and liquid applied sealants. The most common penetrations and details are highlighted in our GM Details datasheet and explains the best method of ensuring they are well-sealed and gastight.

    • Can membrane laps be taped or welded?

      Both are acceptable methods of sealing laps between membranes in most situations however extra care should be taken if welding a membrane incorporating a foil layer, such as Protech GM Super, because the heat from the weld can affect its performance and integrity. On contaminated sites where hydrocarbons or VOCs are of concern, we recommend all laps should be welded and not taped.

Latest Ground Gas Protection News and Articles

Support at every stage - from site investigation to validation

  • 1 Site Investigation

    Step-1Site Investigation Reports including Gas Monitoring Results. We can review these reports and advise routes for compliance.
  • 2 System Design

    gas-Protection-System-Design-930x550Full Ground Gas Protection System Design available. CIRIA, NHBC & Building Regulations compliant.
  • 3 Specification

    Step3Ease of specification with full NBS Plus specifications available for every product. Wide library of standard details with site specific details on request.
  • 4 Installation

    Telephone-Support-930x550-1We are linked to Specialist Installers who are qualified to NVQ Level 2 in Gas Membrane Installation as recommended in CIRIA C735.
  • 5 Validation

    Step-5We have close links with independent 3rd party validation professionals, ensuring your project complies with the relevant building regulations.

Protecting Buildings On Radon Affected Land

Radon is a naturally occurring, colourless and odourless radioactive gas. It was discovered in 1900 by the German physicist Friedrich Ernst Dorn, who was studying the radioactive decay of Radium, itself only discovered by Marie Curie two years earlier. This work was expanded by the Nobel prize winning Scottish chemist Sir William Ramsey, who identified Radon as the heaviest gaseous element, 9 times heavier than air.

In ground gas terms, most radon is produced by the radioactive decay of trace amounts of uranium found in certain types of soil and rock, and as such the levels of gas present are determined by the underlying geology of the site as opposed to any historical usage or pollution.

This type of geology is most common in areas with granite bedrock such as south west England, the Peak District, north east Scotland and Northamptonshire. Aberdeen in Scotland, being known as the... Continue Reading.

Step by Step: How to Provide Ground Gas Protection

Providing Ground Gas Protection

Since 2008, the number of new households in the UK has continued to exceed the number of new houses actually built. Over the last few years, the UK government has dedicated more of its resources to reversing this trend. The 2017 Autumn Budget, for example, committed £15.3 billion of new financial support to house building over the next five years, and included funds for new infrastructure, land buyouts and the creation of five new ‘garden’ towns. The government has also set a goal of constructing 300,000 new homes per year by the mid-2020s, a rate of house building not seen in the UK for nearly 50 years.

The development of greenfield sites alone is not the answer; the remediation of suitable brownfield sites must play a role in helping UK builders achieve the government’s ambitious targets for new housing provision. To this end, a number of initiatives have been launched to help streamline the brownfield remediation process. An understanding of common soil contaminants, the process of brownfield site classification, and the components that make up a comprehensive ground gas protection system is essential for new construction to be built safely over brownfield sites... Continue Reading.



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  8:30am - 5pm, Mon - Fri

  01250 872 261

  01250 872 727


  A. Proctor Group Ltd., The Haugh, Blairgowrie, PH10 7ER





Innovative Construction Products for Over 80 Years.