Hi I am building an extention and I have to lay methane gas barrier will it be crossibng over the DPC making a bridge in cavaty or I just keep this gas barrier to internal leaf.
Problem is if it is to cross cavity then, will I need cavity tray and weep holes? as wall is 8 meters long I never install a cavity tray please help.
Or I can use this gas barrier and insert weep holes am I right or just wasting my time.
Regards