I’m working on renovating a small old 4 stall barn into a guest house in Maine. I’m researching what to do for insulation and frankly feel a bit overwhelmed at the approaches. Any particularly helpful articles out there?
The walls are 2x4s (sitting on 2×6 sills). At first I thought I’d just rip down plywood and fur out the studs and insulate the bays with fibreglass mats. However, I saw some folks saying the Mooney Wall is a better option?
Also, I will need to replace the siding, probably next year (old shingles over plywood sheathing with house wrap). Would zip system be a good upgrade there? And if so would I need a vapor barrier inside?
Replies
A Mooney wall is great way to go because it reduces thermal bridging. I'd do that and blow it full of cellulose. Fiberglass batts are about the last thing I'd choose (https://www.finehomebuilding.com/2012/01/24/buyers-guide-to-insulation). Rather than adding Zip, I'd spend the money on exterior insulation. This article is pretty helpful:https://www.finehomebuilding.com/2018/01/11/choosing-right-thickness-exterior-foam, as is this one: https://www.finehomebuilding.com/2019/07/22/part-1-prepare-a-rough-opening-for-a-nail-fin-window-over-exterior-rigid-foam-insulation
As to the vapor barrier, I'd use one of the "smart" vapor retarders in your climate, particularly if I added exterior foam. Foam is a vapor barrier, and you never want a vapor barrier on both sides of a wall.
https://www.finehomebuilding.com/2017/09/20/prohome-2017-insulation
You probably want to consider the design in total before you start.
Are you saying you plan to strip the outside to the studs? Or just remove and replace the old shingles?
We're remaking our 1927 two-room, board-and-batten cabin built of old-growth pine and oak with 2x4 wall framing into our retirement cottage. We're insulating with Havelock wool. Highly recommend checking out all the reasons to consider wool insulation.