Re-insulate wall?
We have an extremely cold wall in the master closet of our NorCal home. The wall is pretty standard late ’80s build quality for the area: 4″ studs with fiberglass bats, perhaps with not the most attentive application judging by other areas where the insulation is visible.
I thought about removing the sheetrock, adding furring strips, and re-insulating with rockwool or something similar, but there’s obviously a lot of wasted material in that approach.
Alternatively, maybe just adding 2″ strips outside the existing sheetrock, insulting that small gap, then adding a new later of 1/4″ sheetrock.
I don’t know if the second approach–layer on layer–inadvertently creates hazards, such as moisture build up. In any case, I can do the manual labor easily enough but want to make sure I am not creating a long-term problem.
Much appreciate any advice from the community about these two approaches–or even pointing out a third method that I should be considering.
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Replies
PoisedPorpoise,
I will first guess that the closet in question is on an exterior wall or a shared wall with an unheated garage. The most frequent reason for cold walls in closets is separation from room heat. It is probably safe to assume that all the walls of your home are insulated to the same standard (good or bad), so the cold wall is merely demonstrating how little heat is getting to it.
Well fitting bi-fold doors or sliders over carpet can greatly limit air exchange with the warm room air. Adding a two foot thick barrier of clothing on hangers will pretty much seal the deal. Walk in closets are just larger versions with similar defects if the air exchange is impeded.
If you were to start checking other closets on exterior walls you would likely find them cold during winter and if on the sunny side of the house, quite warm in the summer. Aside from cold jammies to put on, the bigger potential problem is mildew forming on the wall or worse in your clothes. My own midwestern closets suffered this mightily. The only option we had was leaving the closets open all winter.
Before going to all the bother of adding insulation, which might not be as beneficial as you expect, I would look to either replacing the existing doors with louver doors. If that is not aesthetically acceptable, then the next option might simply leaving the door slightly open. If not a walk in closet, does the closet have one short side open to the bedroom? If so, a thru wall vent that joins the bedroom to the closet interior would be a good start. Don't cut into the wall blindly. Think and check for electrical or other hazards.
If the closet is sufficiently deep to allow, moving the hanger bar toward the doors will allow air to get behind the clothing. Not stuffing the hanger bar solid will help also. Same for packing any shelves above the hanger bar. Reducing the boxes or whatever is there will allow warmer air to reach the wall.
Please understand that if you still have no air exchange with the room, new insulation will not magically make the wall warm. It will only slow the losses, though hopefully to a tolerable point that you find acceptable. The condensation/mildew risk you remove from inside the closet might now be a few inches deeper. The risk factor is yours to decide. Tearing out the drywall and building out the studs for new full depth batts will not change the dew point behavior though new full depth batts might handle moisture issues differently from surface application.
Be advised that you will be affecting the condensation point in the wall closer to the existing interior drywall layer if you add interior insulation on the cold wall surface. You could end up making the mildew/mold risk a hidden issue. Consider your humidity profiles over the course of a year and judge for yourself.
If you still feel like insulating and doing the work, a sheet(s) of 1 to 1.5" polyiso foam and a skin of 3/8" minimum (1/4" will be too mushy) drywall would be a minimally fussy task provided no electricals are involved. For this approach there is no point to furring strips, just use long screws and shoot through the drywall/foam/drywall sandwhich. Be sure to spot and mark your stud locations and transfer to the new drywall. Makes hitting the studs easier. Tape and mud to seal edges.
Don't forget to peel off the baseboards and other trims and cut back the carpet if you can. No sense leaving a cold strip right at the bottom to become a sneaky mildew farm. Peel off shelf support mouldings and the hanger bar supports, which you will want to re-set forward to door side if possible. This will be a lot of work, so do consider the air exchange options closely first.