Repair a poor roof assembly
Anchorage AK, CZ7. Hot roof garage, existing home from the 70’s. 2×8 roof trusses. New shingle roof, but existing water damage forced me to remove Gyp and fiberglass batts. Furred out the 2×8’s with 2×12’s for greater insulation thickness and reinforce several rotten trusses from the water damage.
Attempted to convert to cold roof, R38 batts, used blocking to keep an open air path. 6 mil vapor barrier stapled to the bottom. Then I stopped….bad move on my part, I know. Should have finished taping, sealing, and gyp.
Really cold weather, no snow, 0F on the roof. Suddenly we have 25F and 12+” of snow. Now I have water dripping through the insulation and pooling on the plastic. From an inspection and pulling back the plastic, my fears confirmed. I have ice crystals on the bottom of the roof decking, and ice chunks on the shingle nails sticking through. My cold air blocking is also moist. Now as a reader of GBA, I have a strong feeling the moisture is from my lack sealing my air barrier properly.
Here’s my question (thank you for reading the discussion):
It’s still winter, and trying to dry the deck underside is challenging at best. How do I seal this, dry this, and be able to continue without further damaging my home? What is the best way to move forward?
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