Hi all, first post here and I can't find any other threads so apologies if this has been done to death.
I want to put celotex in our loft to replace a very thin ancient layer of rockwool. Then I want to put chipboard boards over the central part, leaving the edges (where I won't be walking) with just loose bits of wood to store things on.
The beams are exactly 750mm deep - the question is, can I put 750mm celotex straight in there so there will be a sandwich of plasterboard (the ceiling - celotex - loft board) or do I need to leave any ventilation gap between the celotex and the loftboard? I can't see why I should but I know it's easy to overlook condensation issues so thought I'd ask (can't find guidance online anywhere).
In the longer run I want to take the boards up, put cross battens down and do a cross layer of celotex to cut out cold-bridging from the beams and generally thicken the insulation, then put the boards back down, and I have assumed that this would not have a gap between the two layers of celotex but again I can't find this confirmed anywhere.
Be grateful for any advice.
I want to put celotex in our loft to replace a very thin ancient layer of rockwool. Then I want to put chipboard boards over the central part, leaving the edges (where I won't be walking) with just loose bits of wood to store things on.
The beams are exactly 750mm deep - the question is, can I put 750mm celotex straight in there so there will be a sandwich of plasterboard (the ceiling - celotex - loft board) or do I need to leave any ventilation gap between the celotex and the loftboard? I can't see why I should but I know it's easy to overlook condensation issues so thought I'd ask (can't find guidance online anywhere).
In the longer run I want to take the boards up, put cross battens down and do a cross layer of celotex to cut out cold-bridging from the beams and generally thicken the insulation, then put the boards back down, and I have assumed that this would not have a gap between the two layers of celotex but again I can't find this confirmed anywhere.
Be grateful for any advice.