POWERBASE® Gas and chemical barriers

Powerbase VOC barrier

Powerbase VOC

Multilayered barrier membrane for methane, radon, CO2, hydrocarbons and volatile organic compounds (VOCs).

  • Independently tested to ISO 15105-2
  • Compliant to BS 8485:2015 + A1:2019
  • CE Marking
  • High tear and puncture resistance
  • Available in rolls for joining on site
  • Prefabricated panels option for specified footprints
  • Also acts as a damp proof membrane
Installation Instructions
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Powerbase VOC Top Hat Detail

VOC Accessories & Tapes

  • Full range of tapes and accessories (top hats, corners)
Powerbase Accessories


Powerbase vapour and gas barriers provide protection against naturally occurring hazardous gases and soils contaminated with hydrocarbons or toxic industrial pollutants. They are also used for groundwater and environmental protection installations.
Gas barriers are necessary wherever there is a risk of naturally occurring radon or methane gas. Radon is commonly found over granite formations whereas methane and carbon dioxide is produced as a result of the decomposition of organic matter such as made ground or natural deposits such as coal, peat or silt.
Developments on brownfield sites such as old industrial sites or contaminated land require effective gas barriers to prevent harmful gases, hydrocarbons and Volatile Organic Compounds (VOCs) from permeating into buildings.
Typically, an impermeable barrier is designed in the foundations of the building over a high permeable ventilation layer. Hazardous gases and VOCs migrate up through the soil and collect under the membrane in a sump from where they are vented and safely dispersed into the atmosphere.
The principal function of the gas barrier membrane is to prevent harmful gases from entering the building through cracks, construction joints and service openings in the floor slab. The membrane should cover the whole plan area of the structure to all external faces in order to seal the ground slab as well as any cavity walls and voids in hollow concrete block work.

Special consideration should be given to sites contaminated by Hydrocarbons or VOCs. These are very mobile compounds and will migrate relatively easily through unsuitable membrane materials. Aluminium laminates are superb gas barriers but these materials will delaminate when exposed to hydrocarbon vapour/VOCs; furthermore, the aluminium layer is susceptible to oxidation due to moisture penetrating the exposed edges. A comprehensive range of task-specific engineered barriers and accompanying Accessories provide consultants and design engineers effective barrier solutions and for the contractor a rapid, simple and cost- effective installation.


The next generation innovative engineered barrier membrane

Powerbase VOC is an innovative engineered barrier membrane to prevent the ingress of Volatile Organic Compounds (VOCs) and harmful gases including hydrocarbons, methane, radon and carbon dioxide.

It is specifically designed for developments on brownfield sites or contaminated land. A contaminated land risk assessment will identify the harmful gases and Powerbase VOC is the responsible choice to provide the necessary protection against a broad spectrum of toxic vapours and gases.

VOCs, hydrocarbon vapours and other toxins are found on many brownfield sites, especially land previously occupied by chemical and paint works, timber treatment, petrochemical plants and fuel stores, petrol stations, tanneries, paint factories, paper mills, coalfields, disposal and landfill sites. Some naturally occurring gases are also harmful and these include radon, methane and carbon dioxide.

HDPE and other homogenous membranes, many of which claim to be hydrocarbon resistant, are in fact quite permeable to certain toxic vapours and gases and do not offer adequate protection.

Powerbase VOC is supported by a unique software application, the Powerbase VOC app, a simple-to-use app which provides performance data for a wide range of harmful chemicals. This app is used by design and environmental engineers as part of the risk assessment and is available to download.

Powerbase VOC specified for major development in Southport

Full range of accessories

Easier than HDPE to install

Powerbase VOC is a multilayered hydrocarbon and chemical resistant barrier membrane. It has exceptional resistance to the commonly found hydrocarbons and chemicals. Using the advanced technology of a composite membrane, the Powerbase VOC membrane comprises protective polymeric layers on both sides of a hydrocarbon and chemical resistant inner core.

Supplied in a wide-width 3m x 50m roll offering potential labour savings and a competitive price, Powerbase VOC is the superior choice compared to other leading HDPE membranes on the market.

Powerbase VOC is complemented with a full range of top hats, corner pieces and tapes also available to order.



Hydrocarbon resistant barrier membrane with exceptional and proven resistance to hydrocarbons, methane, radon and carbon dioxide.


Covered installations with low level mechanical constraints, with no risk of puncture or abrasion.
Contaminated land.
Brownfield site development.

Environmental protection.
Water resources and groundwater protection. Secondary containment.
Underground structures.


Installed using conventional thermal (hot air/wedge) welding equipment or proprietary sealing tapes as detailed in the installation instructions.


Rolls should be stored inside, off the ground, protected from sunlight in cool and dry conditions.


Composite membrane comprising protective polymeric layers on both sides of a chemical resistant hydrocarbon barrier inner core.


Compliant with the latest legislation, Powerbase VOC is tested to ISO 15105-2, the test endorsed by CIRIA and NHBC :

  • BS 8485 warns of the use of HDPE/ LDPE single layer type membranes with poor resistance to hydrocarbons for contaminated land projects.
  • BS8485:2015 – The Code of Practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings
  • Ciria C748:2014 – Guidance on the use of plastic membranes as VOC vapour barriers

Powerbase VOC is the reliable solution for:

  • Ciria C716:2012 – Remediating and mitigating risks from volatile organic compound (VOC) vapours from land affected by contamination
  • Ciria C735 – Good practice on the testing and verification of protection systems for buildings agains hazardous ground gases
  • Statutory guidance for Part 2A of the Environmental Protection Act 1990 – Guidance for the regulation of contaminated land
  • NHBC Chapter 4.1 – Land quality – managing ground conditions

The Powerbase VOC app is a unique software application that supports the Powerbase VOC membrane.

Provides site-specific permeation information for contaminants

Easy-to-use for design and environmental engineers as part of the risk assessment

Performance data for a wide range of harmful chemicals

Use the QR code above to register and access the app on a smartphone or tablet.



Colour Weight/Thickness Tensile Strength Nail tear resistance Elongation NHBC gas proction measures Gas permebility Temperature range Water Vapor resistance Sizes Roll weight Pallet quantity



475gsm 500 μm

MD 435 XD 430

MD 310 XD 350

MD 722 XD 715

Green Amber 1 & 2 Red

EN ISO 15105-2 Benzene: 4 g/m2/day Toluene: 4 g/m2/day Ethyl Benzene: 5 g/m2/day Xylene: 8 g/m2/day

EN ISO 15105-1 Methane: 0.14 ml/m2/day/atm CO2: 3.01 ml/m2/day

Radon: 1 x 10-14/m2/s

-40 to +70


3 x 50



VOC Projects


Chemical Resistant Classes at New School

ITP's Powerbase VOC gas barrier membrane was used in the construction of the new Saddleworth School in Oldham, Greater Manchester, which was rebuilt under the Government’s Priority School Building Programme.

View all Powerbase projects

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