Vapour barrier

On the warm side - so just behind the PB (or use foil lined PB).

Chances are there will not be that much warm wet air in the building by the sounds of it, but for the effort involved to tack a plastic sheet behind the PB you might as well.

you need some sort of moisture barrier inside the insulation. consider foil backed plasterboard.

Or best of all, celotex wedged between joists and foil taped over the joins

vapour barriers are on the whole over rated and not required ....

Yes, between plaster board and insulation to prevent interstitial condensation.

Mike

Thanks all,

I'm intending to do this as cheaply as possible as I already have 4 half sheets of plasterboard left over from previous jobs plus enough insulation, again from stock in my spare room.

I've now purchased some material for the moisture barrier from SF for around a tenner and boy does it stink! I had it in my kitchen for around

Also from my stock a couple of lengths of stud timer - very slightly banana shaped now but it will do. This is not the best wood in the world but on the label it says it is suitable for buildings AND BRIDGES! I do hope when I next cross a bridge that the builders found something a lot better :)

Is this something to do with breeding racehorses?

John