Best way to improve 2×4 stud wall air sealing in 1960’s house ?
A friend is renovating the living room in a recently purchased house that was built in the late 1960s. Location is in the mountains of Virginia, climate zone 4. The exterior wall construction (outside to inside) is: Horizontal lap siding, diagonal board sheathing, asphalt felt paper, 2×4 studs with kraft faced fiberglass batts, interior plywood paneling.
My friend is removing the interior paneling, partly because there are no protective metal plates over the wiring routed through studs. He plans to add protective plates then cover the walls with drywall. The original fiberglass insulation is installed with the kraft backing loosely stapled along the sides of the studs, not lapped over the stud faces.
The wall construction does not have an effective interior vapor barrier. I dont know if the asphalt felt paper represents much of an exterior air barrier. My guess is that the wall is quite leaky and could be improved since the interior paneling is being removed and the insulation will be exposed.
What is the best approach for improving the wall ? Is it safe to add a 6 mil poly vapor barrier across the studs before installing drywall ? Is there any advantage to reinstalling the paneling, then putting drywall over it ?
Thanks for any advice.
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