Using Celotex

[wadge]

Bit confused here. I've got a single skin block wall which I want to insulate with Celotex.

So the plan is as recommended by their website:

Wall - Celotex (with joints sealed by foil tape) - 25mm battens screwed through Celotex into wall - plasterboard screwed to battens.

The website talks about using a membrane...where does this go and which way should it face? Can I use the same breather membrane like I used under the roof tiles?

Should I use a polythene sheet inbetween the block and Celotex to stop water coming through?

[mikric]

Normal application is to put the membrane against the outside wall then the celotex, but in theory its up to you, the foil backing on the insulation acts as a vapour barrier in itself.

[wadge]

Thanks. The barrier membrane has printing on it saying 'face this side out'. So does that face the inside of the room or the brick?

[mikric]

would take out ,to mean outside skin maybe