Ok. I may have made a mistake. Tile roofing.
I have a well-made 1227 brick two story with plaster/lathe walls. The hipped roof is Ludovici Spanish glazed terra cotta tiles (original). My home is in zone 5, just north of Chicago.
https://ludowici.com/product/spanish13/
When I bought home I replaced the boiler (hot water radiators), installed a raised sewer and sump, and spray foamed the bottom of the rafters (to bring the attic into the envelope. I think this de humidified the space too much. I wanted to install a heat pump in the attic with humidifiers. That was six years ago, money issues. Since then I have tuckpointed the house.
Two issues:
1 I have developed major cracks in the walls on the first floor. The attached brick porch began subsiding. It had been stabilized 17 years ago and the original contractor covered re-raising it!
United Structural Systems of Illinois, Inc.
I don’t think this was influenced by the work I had done…But maybe?? This is the major reason I want to control the humidity in the house.2 Here’s where my major question is. I did develop a roof leak maybe due to shifting of the house, maybe not. It was fixed, but I want to now restore the roof, both house and garage. The underlayment is mostly 93 years old. I’ve gotten a couple of different prices and WOW. From $35K ++ (broken tiles and bad wood) to $75K++ (again tiles and bad wood).
Is there and underlayment I can put up to allow vapor to leave the wood, since I freaking sealed the back side with spray foam?
Thanks
Replies
30# asphalt coated felt (tar paper)
What makes you think the spray foam caused any of this? It's pretty common to apply closed cell spray foam to the underside of a roof...
I don't think that any of this was caused by the closed cell foam. Except maybe drying the house.
But, I don't want to screw up the roof restoration and over water seal the roof decking. I'm worried about wood rot in the decking.