timberframe exterior wall membrane

[aidf72]

Hi,

I've got a timber-frame property, (ground floor external is brick, first floor uPVC cladding) and I want to upgrade the insulation behind the plasterboard on the external (and party) walls. I've read about membranes in insulation literature and I can see what appears to be plastic sheet poking out at the bottom of some of the walls. Is the membrane special or is it just plastic? what's it called? where do I get it? and has anyone got any links to useful info or advice?
many thanks.
Aid.

 

[Deluks]

here

essential for the warm (room) side of the insulation. It prevents water vapour (from cooking/drying clothes/washing/breathing/sweating etc) from passing through the insulation, which then condenses on the cold side of the insulation causing damp/mold. Not necessary if you are using kingspan (foiled) insulation boards or use foil backed plasterboard.