I have aircon cooled 4x2m room planned in the NE corner of the basement. So two external walls, and internal block wall and doorway, and a fourth wall to be constructed. Latter is what I'm interested in.

 

I was planning on building a standard 100mm stud wall, filling with rockwool and lining the cold side with taped 100mm foil faced PIR. Finish TBC but likely some sort of plastic bathroom paneling type system.

 

Other side of the stud wall is the plant room. Was going to out another 50mm of PIR on this side, then screw on sheets of either ply or OSB to form a mounting surface.

 

Do I need to consider a vapour barrier? Would this go on the warm side?

 

Would this build up be sufficient or should I be looking at some sort of twin wall / cavity build up? I concsious that this design doesn't allow me to easily mount anything to the cold side wall.

55 minutes ago, Conor said:

Do I need to consider a vapour barrier? Would this go on the warm side?

I would say yes, to both.

Anybody else? I'm now thinking a twin stud wall with 100mm gap for PIR. Will allow me to screw in on either site of wall. Vapour barrier behind the ply on the warm side.

 

sounds like a more useable option.