1974 construction retrofit
A friend is looking to replace siding and windows on his 1974 house in climate 4 marine. The main floor and upstairs walls are 2×4 and the basement walls are 2×6. There is timber framing inside that I suspect bridges to the ext sheathing w/o any insulation. Where he has removed some of the vinyl siding, he found fiberboard sheathing (R1.32 stamped on it). I don’t know what is under that. (The garage is just studs + fiberboard + siding). The gable walls have 3″ overhangs and the roofing is 2 years old.
The wind can be felt inside the house at any given time and there is bulk water intrusion at some of the windows and deck attachments.
That is a concrete sky bridge going to the front door – the Google photo doesn’t do it justice!
The first quote he got was far beyond his budget. I suggested he do all the work up to the top of the rake walls, ~13′ (and hire out the upper).
I suggested he remove all the sheathing (progressively, in sections), remove any insulation and air seal j-boxes, replace insulation, Zip + tape the walls. Once the entire house looks like a Huber advertisement, then add 2″ of EPS and reside the house.
Is Zip + tape suitable under the EPS or should there be some Tyvek too?
If there is some poly behind the sheetrock, should it stay or go?
How would he insulate the inside of the rim joist from the exterior?
Is a rain screen over the EPS a necessity?
What does he do about a lack of overhangs on a new roof?
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