Morning all. Just joined and this is my first post. I love to DIY and am looking forward to creating my man cave. I've got single brick, flat roofed workshop attached to the rear of my garage. I want to make a multipurpose room with a fold down work surface, tool storage area, microbrewery and TV/gaming room. It needs insulating first and I'm thinking battening using 38mmx63mm studwork timber from wickes and using 50mm celotex. I shall be using OSB instead of plasterboard on 3 of the walls and the ceiling and cladding the 4th wall with timber I've recycled from old wooden pallets.
My questions are
1. Will I need a damp proof membrane against the brickwork?
2. Is the 13mm air gap between the celotex and osd/pallet wood ok?
3. I want to use dimable downlights in the ceiling, is celotex ok to use or is there something better?
Many thanks
John