DPC to cope with Methane?

[tvrbeaver]

I have a special clause on my plan application approval, that says the barrier under my concrete oversite has to cope with Methane?... this is due to us being within 150 meters of some old land fill I guess....
Having contacted building control, they say its yellow in colour with ali foil in the middle... but I can't find it at any of my local building murchants?...
The other option is to use standard HDPE sheet but it must be grade 1 (made from vergin material) and again I can't find this.

what are other people using for this application?

Thanks

 

[tony1851]

A lot of this is a con by the manufacturers.

1200g plain polythene is perfectly OK as a barrier (in conjunction with correct detailing at the walls). The stuff sold specifically as gas barriers is basically the same, but with reinforcement added to reduce the risk of puncturing or tearing. This therefore allows for a degree of rough handling. If you are careful, and lay it on a well-compacted smooth bed, it should be fine.

Problem is, while the manucturers recommend their (expensive) reinforced sheet, they don't say that ordinary PE won't do, and inspectors go by what the manufacturer says.

 

[tvrbeaver]

I’m told by building control that Methane gas barrier is designed to stop Methane passing through it. On a molecular level, Methane is small in comparison to Water, Radon, CO2 etc.. so even membranes that hold water will not stop Methane?....

The barrier is made from virgin HDPE to give a total seal?....

Not sure if it’s bull or what.. but I don’t want to be taking the oversite back up…