Methane is generated in the underground and for the most part it percolates to the surface and dissipates under normal atmospheric conditions. Under these circumstances the gas does not constitute a health hazard. However, when buildings are constructed on gas contaminated land, it will seep into buildings through openings, construction joints, cavities and service penetrations to reach a dangerous concentration posing a serious health hazard to the inhabitants of the building.

A high concentration of methane gas can be naturally occurring dependent on the geological structure but is furthermore often found on ground that:

  • previously has been utilised for industrial processes such as chemical factories by spillage of gas-generating chemicals and heavy hydrocarbons
  • has been used as landfill where the breakdown of organic material by micro-organisms under anaerobic conditions produce landfill gases of methane and CO2.  A thorough site investigation is usually required to determine the concentration.

We carry the following methane membrane as standard:

Monarflex Reflex Super radon barrier is a high performance, loose-laid membrane developed specifically for use in the foundations of new buildings on contaminated sites where landfill gases exist e.g. methane and CO2