I have a manufactured home from the 70's with metal siding, wood studded walls and fiberglass insulation on the inside. I had a clogged gutter, which caused water to run behind the siding, around the window, into the house and made the drywall & insulation soggy. Then I accidentally poked a hole in the drywall. There is a noticeable draft coming from the hole in the drywall and the wall has always been seemed poorly insulated.

I cleared the gutter and the wall dried out, but now I want to fix the damage.

I was planning on just taking out the 8 feet or so of drywall and replacing it and the insulation, but I want to do it the "best" way possible. So what would that be? Using pre-faced insulation? Unfaced insulation with vapor barrier and sheathing tape? Does the vapor barrier go on the warm side or the cold side? Can you recommend any particular products?

Bonus question: Can you recommend any good DIY books on the subject?

  • There are two different brands at the two major big-box stores in the US. I've used both and anecdotally, the JM (at Lowe's) seems to have stronger craft paper backing, while the Owens Corning (at HD) has a printed pattern that repeats every 2', making it very easy for me to cut pieces to size for my 8' wall cavities. – Niall C. Mar 19 '11 at 15:45

Since you're going to have the walls open, I would use pre-faced fiberglass batting. The rolls give you more flexibility than the pre-cut batts if you have non-standard height walls and they're usually a little cheaper per square foot, but I see special offers in the big-box stores all the time so shop around.

There's no special trick to installing it, but wear a dust mask that's rated for fiberglass dust. The vapor barrier goes on the warm side. I usually cut pieces to length before installing them in the wall (but I'm an engineer and can't help myself! :), but you can cut it to size while it's in the wall if you're not as OCD as me: put the loose end at the top of the wall, unroll and stuff until you reach the bottom then cut it off. Run a bead of adhesive along the stud, then unfold the flaps at the edge of the insulation on one side of the stud and press into the adhesive. Repeat for the insulation on other side, then staple the two of them into the stud. Tap the staples in with a hammer if they didn't go all the way. Done!

I don't have a book recommendation, but it's easy to learn how to do it.

  • The walls are a weird height (slightly less than 8 feet) and the has several windows, so a roll sounds like the way to go. Thanks! – Greg Mar 19 '11 at 15:40
  • 2
    Using adhesive on the studs under the flaps of the insulation is definitely a unique step, never seen that done on any job, not that it is a bad idea. Wether or not the insulation has a vapor barrier backing, we use a 4 mil poly vapor barrier over the wall and tuck tape the seems, top, etc. before installing sheetrock. I will caution you however, if you use an adhesive, be absolutely sure it is applied thinly and compressed fully. If ridges of adhesive harden on the studs, hanging your rock will be difficult and result in uneven seems. – shirlock homes Mar 20 '11 at 11:59
  • Thanks for the tip, @shirlock-homes. I was wondering about the adhesive step. I got myself into trouble with adhesive recently and I'm weary of making things too difficult to tear apart when I mess it up. – Greg Mar 21 '11 at 17:32

Your Answer

