Thanks so much Dan, I'm thinking that during the cold wet months we've had recently the moisture from the inside has been collecting up there and being absorbed into the OSB and staying there due to the roof being covered in felt. Now that we're having warm weather the sun is beating down drying it out and causing it to drip down into the room.... does that make sense? Is that how physics works?Waka wrote:As an alternative temporary measure, you could add exterior thermal insulation to your roof deck (celotex or something similar) and put felt on top of that. So you would have a warm roof then. As your roof is almost always the biggest problem, this might be good enough in the mean time. Then when you build your outer leaf, just move the celotex to the outer roof deck.
If you do this, follow the correct warm-roof design for your area (not sure about wales building regs). You will probably need to replace your felt with a vapour control layer.
Dan
Regarding the warm roof idea, I agree with you; this was my first thought. I am planning to have a warm roof anyway once I do my outer leaf, and I do have a load of celotex here handy, which is good because every builder's yard in the local area is closed right now due to the lockdown.
I better research if celotex is vaporr permeable or not though, because if it's not then surely it will just be making the problem worse?
I also can't build my silencer boxes due to the lockdown, but I could just cut some holes where the sleeves of the boxes will go and then put a little shelter on the outside for them?
In regards to where the silencer boxes/vents are positioned, would it be better to have them up high or does it not really matter once the fan is in there moving the air?
I went up on the roof and couldn't see anything obvious, there are seams but they are all overlapped really well and have a bead of roofing silicone under them, I went ahead and went over some of the seams again anyway just in case. Where I thought I saw a leak is actually in the middle of the roof.
Other alternatives I thought of are:
Taking out a load of the insulation that I put up, maybe that peak "corner trap" is causing the majority of the problem.
Leaving the doors open with a fan inside should temporarily help.
I could even cut a ridge vent in and then seal it back up when I do the outer leaf... I wouldn't really be able to cut soffit vents in though, not with out some major operation.
Thoughts?
Paul