Hi All
First post here, and after spending hours trawling through here seeing similar things discussed but not quite the same as my situation thought I'd post to gain some sound advice.
We have a garden outbuilding - that's now used as a garden office. We're relatively new to the house but building was clearly fine before (i.e. no damp, leaks, condensation). But felt roof got damaged and water then got in. To the point we're now about to have the roof re-felted (or GRP or Rubber) and new plasterboard put up inside. Upon revealing the inside of the ceiling I can see there is only 75mm joists (entire gap from ceiling to roof OSB boards) and that was filled full with rockwool or equivilent of.
My understanding is, being a cold roof, it should have a gap (ideally 50mm) above any insulation, but this is going to prove tricky when I've only got 75mm in total to play with. And to add to it there's no ventilation at all, and I can't see how this could be added currently as one side is brick (and to have it both sides, and along about 10 different joist gaps).
So I'd love to know your thoughts on how best to proceed. If the OSB boards are being exposed do I build a warm roof and is that relatively straight forward, i.e. just adding a VCL and Kingspan and then re-felt/layer, or if I stick to the cold roof do I have to either have mushroom vents (and lots of them!) or can I fill full (like it was before) and add a VCL above the plasterboard ceiling?
Any thoughts well received - don't want to get this all finished and then have condensation dripping through!
First post here, and after spending hours trawling through here seeing similar things discussed but not quite the same as my situation thought I'd post to gain some sound advice.
We have a garden outbuilding - that's now used as a garden office. We're relatively new to the house but building was clearly fine before (i.e. no damp, leaks, condensation). But felt roof got damaged and water then got in. To the point we're now about to have the roof re-felted (or GRP or Rubber) and new plasterboard put up inside. Upon revealing the inside of the ceiling I can see there is only 75mm joists (entire gap from ceiling to roof OSB boards) and that was filled full with rockwool or equivilent of.
My understanding is, being a cold roof, it should have a gap (ideally 50mm) above any insulation, but this is going to prove tricky when I've only got 75mm in total to play with. And to add to it there's no ventilation at all, and I can't see how this could be added currently as one side is brick (and to have it both sides, and along about 10 different joist gaps).
So I'd love to know your thoughts on how best to proceed. If the OSB boards are being exposed do I build a warm roof and is that relatively straight forward, i.e. just adding a VCL and Kingspan and then re-felt/layer, or if I stick to the cold roof do I have to either have mushroom vents (and lots of them!) or can I fill full (like it was before) and add a VCL above the plasterboard ceiling?
Any thoughts well received - don't want to get this all finished and then have condensation dripping through!
