Add poly-iso as thermal break to exterior?
hurnik
| Posted in Energy, Heating & Insulation on
I’ve got an old 1950 cape cod. 2×4 construction, 3/4″ shiplap, then tar paper, then cedar shingles (about 3/4-1″ due to overlap), then they put on some 1/2″ furring strips on top of that and then vinyl siding.
I’d like to remove exterior stuff down to the studs (don’t ask, just easier than removing all the interior sheetrock, crown molding, mudding/taping,painting, etc.)
Is it wise to add 3/4 or 1″ poly-iso on to the exterior 2×4, (blown in cellulose into the stud bays), then adding some strapping/furring strips, and then sheathing as a form of a thermal break? (then something like tyvek, then put the vinyl siding back on?)
Or do you put the OSB on the 2×4 and then add the poly-iso and then the furring strips/vinyl siding?
Replies
You could leave
the shiplap in place (it's flat, not bevel..?) and install the foam over that, followed by furring and new siding. You might want more than 1" of foam, depending on climate zone.