Hello,
I have been approached by some homeowners with a SIP timber frame house built in the 90’s which has black water dripping down from the beams in the late winter of every year. My thought is that the SIP seams are over the beams were not properly sealed, and so warm moist air freezes on the underside of the tar paper and then thaws out and drips into the house in the spring. I proposed that we pull the metal roofing off, apply peal and stick underlayment to the entire roof and then install a new roof. I’m looking for a second opinion. Has anyone tried anything like this? Do you think it will work?
Thank you!
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Vapor barrier has to be on the warm side.
Unless you are adding a lot more insulation on top of the peel and stick, it will do nothing to solve the suspected problem.
Blower door test to find the air leakage locations, and seal that up from the inside.
I agree with catmandeux. A couple of additional things - you don't necessarily need a blower door to create the differential pressure that will illuminate the air bypasses. Just turning on every exhaust fan (range hood, bath fans, clothes dryer) can do the job. You can use an IR camera in addition to the fans exhausting air to highlight the precise spots where air is leaking.
Part of the problem may be air leaking to the exterior through the joint at the ridge. That's in addition to vapor control layer continuity.
If the root problem is air leaking then it may be possible (emphisis on 'may') to air seal between the ceiling finish and the beam to stop the winter air from reaching colder areas of the SIP panels.