Air Sealing/insulating with fiberboard sheathing
I have an interior renovation project located in central Pennsylvania (Climate Zone 5). The home was built in the 1960s. New vinyl siding, cheap woven house wrap, and new windows we’re installed 4-5 years ago. On the interior, we have removed the existing plaster and insulation. The exterior sheathing is fiberboard, which is in poor condition. It appears the fiberboard sheathing took a beating when the new vinyl siding was installed. Also it does not appear the housewrap was not installed correctly as I cannot find any laps or slices that I’ve been taped. Air sealing seems like it will be a challenge.
Removing the vinyl siding, woven housewrap, and fiberboard sheathing is not an option. Air sealing has to be performed from the inside. Due to the flow of the project, structural modifications, MEP rough-in, and various code inspections…we are roughly 4 to 6 weeks from being able to insulate. Currently temperatures are in the 40s and low 60s, however in 4-6 weeks temperatures will be in the 30s and 40s.
With this in mind, what is the best way to air seal (from interior) and insulate the wall assembly? Close cell spray foam probably won’t be an option due to crew availability, temperatures, and cost. Is the cut and cobble method an acceptable approach? Or is another approach best? Code requires a vapor retarder on the warm side of the wall assembly.
Any insight would be appreciated. Thank you. Jared.
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