Do I need a vapour barrier when dry lining?

[paddypower]

I?m dry lining a room by using 2X1?s with 38mm insulated plaster slabs screwed to them, thus leaving a 1? air gap. Do I need a vapour barrier between the slabs and the battens?

regards

 

[jeds]

You should never put a vapour barrier on the cold side of insulation - it will have the opposite effect and trap condensation moisture.

If I'm reading you right you are going to use insulated plasterbord - i.e the stuff that comes with the insulation bonded to the plasterboard in one unit. This stuff already has a vapour barrier within so you do not need to add another. A certain amount of vapour can penetrate the joints so you must seal the joints as you go.

If you are intending using insulation slabs and then a plasterboard sheet over then you should put the vapour barrier between the plasterboard and the insulation. (i.e. the warm side of the insulation)

 

[paddypower]

Thanks for that, you've read it right, Kingspan thermal board. What sort of tape should be used? I was just going to scrim before the plasterers skimmed it.