MB420 Gas Membrane

MB420 Gas Membrane is a high performance gas membrane for use in situations where resistance to methane, carbon dioxide and/or radon gas is required. It is generally used within construction applications, predominantly within the foundation design. The multilayer 0.7mm thick membrane includes an ultra-low permeability aluminium foil core encapsulated between a number of additional LDPE layers and a reinforcing grid to form a single sheet membrane.


  • Excellent resistance properties with low permeability to ground gases including methane, carbon dioxide and radon
  • Provides additional damp proofing protection to the structure (no requirement for a separate DPM)
  • Reinforced membrane construction with excellent resistance to both puncturing and tearing
  • Complies with relevant industry codes and guidance including CIRIA and BRE


The use of the MB420 Membrane is suggested where combined gas protection and damp proofing is required. The membrane is a loose-laid product suitable for use in most horizontal and some shallow vertical including beneath reinforced concrete slabs and associated foundations.


Suitable for use in conjunction with the Gas Resistant Self Adhesive Membrane and Gas Resistant DPC for protection against the ingress of methane, carbon dioxide, radon and damp.

The MB420 membrane can be installed with the use of either welded or taped joints depending on the specific project requirements. 

Product VOCs including hydrocarbons Methane Carbon Dioxide Radon
Gas Resistant Self Adhesive Membrane
Puraflex Tank VOC Membrane
Radon Membrane
MB420 Gas Membrane
Puraflex VOC Membrane


Note: All membrane types also provide damp proofing protection, however should there be the additional risk posed by hydrostatic water pressure, please contact a member of the Cordek Technical Team for additional advice.


Data Sheets

Product Issue Date Version Size Download
MB420 Gas Membrane Data Sheet 02/2019 6 243.4 KB

MSDS Data Sheets

Product Issue Date Version Size Download
MB420 Gas Membrane MSDS 05/2017 3 119.8 KB


Product Issue Date Version Size Download
VOC & Ground Gas Protection 01/2018 3 5.0 MB

NBS Clauses

Our NBS Clauses are hosted on the external website - view NBS Clauses

BIM Library

Please select the BIM file in the format you require.

Name IFC Size IFC Download Revit Size Revit Download
MB420 Gas Membrane 10.7 KB 936.0 KB

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