Hey everyone, First the back story, I am in new england, my house has a ~3/12 pitch and the previous owners thought they were being smart by converting it from a tar and gravel roof to an architectural shingle roof, but the pitch is too flat and the water was completely soaking and pouring through in less than 5 years.
So we decided to go with a standing seam roof. When we opened it up we found extensive damage from moisture (we live on a lake) because their were vents in the soffits but not at the top/ridge. The roof is slightly complicated because the main part is a 4-sided pyramid with a giant skylight in the middle so there is no ridge vents anywhere around there. In some cases the rafters had completely rotted away at the top, presumably from trapped moisture:
The only places the rafters were still solid was where they weren’t connected to the vented soffits, such as in the valley and above skylights. So after seeing that empirical evidence and researching it I decided to convert the entire roof to a sealed cathedral ceiling (interior has a cedar over plywood cathedral ceiling on most of the house and drywall ceiling attached directly to the rafters in the most problematic place).
So I ripped out the old soffits and block insulated and spray foamed all the gaps between the rafters:
And the new roof was installed:
Now, 3 summers later, for the first time, I am getting drips from some of the recessed lights and the top door moulding on the wall, and this is on humid days (basically all of July here), more than a week after the last rain storm. We don’t have air conditioning so I didn’t think the inside could be getting cold enough that it could cause condensation, but I have no other explanation for where the water is coming from. I double checked and recaulked any possible seams in the roof above that spot but it continues, again no where near a rain storm. The area where it is is dripping from most is fully insulated, then has plastic vapor barrier attached to the bottom of the rafters, and then drywall on that. I pulled out the recessed light (old-work, not air-tight) and the insulation feels soaked and water could literally be wrung out of it. Seems like more of the water runs down the vapor barrier to the wall and is making the drywall bubble a bit.
If this is a condensation problem, which everything so far points to, then what are my options without ripping off the whole roof and putting baffles and soffit/ridge vents? I could pop off the ridge cap pretty easily and cut a vent into the top of the decking along the ridge beam and at least add a top side vent. Or do i need to pull down the drywall and re-insulate/sprayfoam the bottom of the roof deck? Thanks for your help.