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Old 1950's house in zone 4 has no insulation in the walls. In zone 4 I believe we want the insulation batt face pointing inward, but how to you staple the tabs from the outside? Is there an acceptable way to install batts from the outside to prevent them from falling down?

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  • Actual carpentry, before plywood. Waow.
    – Mazura
    Aug 5, 2023 at 21:52

2 Answers 2

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Assuming those are standard wall cavities, minimal wind, no rain, and you're using the correct width batts then they should just friction-fit long enough to put sheathing over them.

The other concern which is harder to address is vapor barrier.

Ideally, one would overlap the tabs like so: enter image description here

Obviously, that's not feasible for you.

Letting the tabs rest on the inside of the studs is also acceptable: enter image description here


The biggest possible demise for insulation in general is compression so keep it fluffy and you're good to go.

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  • If it was not so much a PITA to do, I would recommend the 4 or 6 mil plastic barrier and plain/unface batts, just for the better draft stop.
    – crip659
    Aug 4, 2023 at 17:42
  • @crip659 If OP has plans to tear apart the inside of the house then they could choose to add that later if they wish for such superiority. You can fairly cleanly pull the face off the batts.
    – MonkeyZeus
    Aug 4, 2023 at 17:55
  • I just learned about vapor barrier. Doesn't seem like an option for me, but according to research I did on Green Building Advisor (greenbuildingadvisor.com/article/do-i-need-a-vapor-retarder) the bigger issue is air barrier, so I am taping my seams on plywood sheathing, and then using a high perm house wrap. Internal vapor barrier is a no go sadly. Update: I went back and contractor install the insulation face out, made him fix that...learning fast (and I won't use this contractor again). Also good call out by @MonkeyZeus saw some batts that were too long and stuffed in, made them cut it
    – Beedlebumm
    Aug 5, 2023 at 18:29
  • friction-fit long enough - Don't start this at 4:30 on a Friday and expect it to still be there Monday without sheathing over it. Hell, you can't even take lunch.... You're "using a high perm house wrap" - then w/e. If it was blown-in then there'd be nothing anyway. And always, "Beware the moisture vapor barrier sandwich."
    – Mazura
    Aug 5, 2023 at 21:45
  • @Beedlebumm I'm glad you found my answer useful and made the contractor correct their mistakes. As much as a bad rap that inspectors receive, these are exactly the types of things which they force unknowledgeable contractors to fix.
    – MonkeyZeus
    Aug 7, 2023 at 13:03
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Install a vapor barrier against the drywall, and then push in un-faced batts (or spray in damp-spray cellulose. informational link, not associated)

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