I have recently bought a 1970s crosswall house.
All my external walls are studwall. There is no brick outerskin.
I believe there is some ancient rockwool between my studs, and then plasterboard over that internally. I can't quite tell from the gap I've been peering into where any VCL is fitted at the moment.
I am thinking about pulling off the plasterboard. Removing the old rockwool. And putting celotex between the studs. The wall isn't very thick so I don't think I will actually get much celotex in there - but it has to be better than some ancient rockwool! My walls in total are ~200mm thick from inside face of the plasterboard, to the external render. I am hopeful that I could get 50mm celotex in.
So questions:
1) I believe I need a VCL on the warm side of that - how do you seal that against the ceiling / floor / party wall / other internal walls? I am going to end up doing this one room at a time so I think I am always going to have some gaps at the ceiling / floor, and the internal walls. Is that a problem?
2) I know ideally you would have another layer inside to stop the studs being a thermal bridge. But that would result in losing floor space, and having to move electrics and plumbing which turns this into a much bigger job which I'd like to avoid. Is it actually going to cause me problems? Or is it just less benefit than I could have? I've read about shadowing etc, but I am unclear how much this should concern me.
3) In terms of a VCL - Is there any chance my existing VCL is on the OUTSIDE of the rockwool? And if so is there any problem putting more insulation inside that provided I have another VCL inside.
4) My plan would be to use foil backed celotex - however I would probably still apply a continous VCL sheet inside that fixed to the studs. Do I still need to tape up the joints in the celotex in that case?
All my external walls are studwall. There is no brick outerskin.
I believe there is some ancient rockwool between my studs, and then plasterboard over that internally. I can't quite tell from the gap I've been peering into where any VCL is fitted at the moment.
I am thinking about pulling off the plasterboard. Removing the old rockwool. And putting celotex between the studs. The wall isn't very thick so I don't think I will actually get much celotex in there - but it has to be better than some ancient rockwool! My walls in total are ~200mm thick from inside face of the plasterboard, to the external render. I am hopeful that I could get 50mm celotex in.
So questions:
1) I believe I need a VCL on the warm side of that - how do you seal that against the ceiling / floor / party wall / other internal walls? I am going to end up doing this one room at a time so I think I am always going to have some gaps at the ceiling / floor, and the internal walls. Is that a problem?
2) I know ideally you would have another layer inside to stop the studs being a thermal bridge. But that would result in losing floor space, and having to move electrics and plumbing which turns this into a much bigger job which I'd like to avoid. Is it actually going to cause me problems? Or is it just less benefit than I could have? I've read about shadowing etc, but I am unclear how much this should concern me.
3) In terms of a VCL - Is there any chance my existing VCL is on the OUTSIDE of the rockwool? And if so is there any problem putting more insulation inside that provided I have another VCL inside.
4) My plan would be to use foil backed celotex - however I would probably still apply a continous VCL sheet inside that fixed to the studs. Do I still need to tape up the joints in the celotex in that case?
