Roofing Talk - Professional Roofing Contractors Forum banner
1 - 1 of 2 Posts

· Registered
1 Posts
Discussion Starter · #1 ·
Hoping for some insight with a condensation issue we’ve been having with our cathedral roof. We just purchased a home last year which has a new roof installed just two years ago. We noticed that condensation was collecting on exposed beams on the ceiling, so we hired a contractor, opened it up via the ceiling. The previous roofing contractor had not installed a ridge vent, and stuffed the space full with insulation, though there are small soffit “vents” (really just 2 1/2” drilled holes).

Our contractor drilled 3” holes in the rafter cross-beams, used high density batt insulation that leaves a 3” clearance, put in a ridge vent, and re-drywalled. However, after a cold front we live in California and it got to 25 degrees), condensation was dripping from the underside of the roof and down the beams even more than before.
he opened it up in a spot, and there was a significant amount of condensation on the underside of the roof sheathing, but about 12” of the top of the sheathing, nearest the ridge vent, was dry. Our contractor is of the opinion that we just need more ventilation. In the form of bigger soffit vents or low profile vents in the roof.
Building Lighting Interior design Fixture Wood

Wood Fixture Building Composite material House

Wood Beam Floor Hardwood Ceiling

But I worry about a few things and think he may be incorrect. I’m hoping for other insight. Here are some of my concerns.

1. I think the original roofing contractor put a radiant barrier on the inside of the plywood roof sheathing. I think this is incorrect because it encourages condensation. Is this true? Does it HAVE to be removed? (See attached picture) Or is it ok under certain conditions? I’ve read that there needs to be an air barrier so the warm home air doesn’t enter roof space to condense in the fist place. When you’re in the process of putting up drywall how do you prevent this? Also, we have recessed lighting. How would you prevent air leaks?

2. Are the cross-beams impeding the flow too much even with the drilled holes? If they are, how would we fix this issue?

Now that the drywall is up I would hate for him to have to take it all down as it is a MASSIVE space, but we obviously have to get this resolved. Thanks in advance for any help!
1 - 1 of 2 Posts