Question about adding insulation to closet

[zak77]

Ok so this isnt about my garage but about my master bedroom closet. The closet is about 5x6 and sits at very back left corner of my Ranch so 2 of the walls of the closet are exterior walls. It's not heated except for whatever heat makes it way in there from the bedroom. My issue is when it gets below about 15-20° outside i can see condensation forming on the interior drywall of the exterior walls, but more on the side of the house with the eaves. So, obviously that wall in particular is getting too cold. My house was constructed of 2x4 exterior walls with fiberglass batts, vapor barrier(not mentioned earlier), along with 3/8" Faced Polystyrene on the outside of the plywood sheathing.

So far i've installed a floor vent that went down into the basement trying to get some air movement, didnt work all that good, put a vent above the door so more air can move but that didnt make much of a difference either. So without tearing out the drywall, using spray foam then re-drywalling i was contemplating what if i put 1" XPS foam board on the existing drywall for the 2 exterior walls then put drywall over that. I already have r-38 cellulose in the attic however given that the house was built in 1990, i'm sure it's the lack on insulation directly above the top plate that isnt up to snuff. I'd also like to put XPS and foam around all the proper vents up there but that's on the list for sometime in the future.

So is putting foam board over drywall then putting drywall over that asking for issues?

 

[txvwnut]

Knock the drywall out and check the vapor barrier and repair or install a new vapor barrier then new insulation and drywall. Putting foam board over the existing drywall is just masking the problem and not fixing it.

 

[rburke65]

I can appreciate your reluctance to removing the dry wall, but it is what I would do. There isn’t much room to work in a closet....I know....but I’m thinking youll be better informed of what you actually have there.

 

[ace10]

Leave the door open in the Winter?

 

[850xpeps]

Knock the drywall out and see what’s going on. No difference if your drywalling over top. You still need to patch.

 

[zak77]

Well i'm not sure what you think i'll find but when i repainted the closet a couple years ago i poked a small hole in the drywall, yeah i had the joint compound and putty knife out already, and i could clearly see a vapor barrier and insulation. The only difference between the closet and rest of the house is it's "isolation" from being heated like the rest of the house. I'd think this wouldn't cause condensation but what i see before my eyes proves me wrong.

FYI i have left the closet door open and it seems to help. Also when i repainted the closet i found that having clothes, especially a suit coat in a bag, caused more condensation/mold on that section of drywall. Once i moved the clothes away from the wall it helped. Also, there is no plumbing above and it will happen irregardless of rain so it's not an exterior moisture issue.

I'd be more inclined to put a fan that pushes air from one level to another to get air movement in there. I put one in another section of the house to circulate the air, i burn wood in the basement, and it works well. It still doesnt fix the issue of those walls not being insulated enough. I could rip out the drywall, put in different insulation or add 2" spacers to the existing 2x4's so i can get the insulation equivilant to a 2x6 wall then re-drywall.

 

[MattT]

Sounds like the closet walls are getting cold enough to condense water out of the indoor air. If it's just started this year have you done anything to raise indoor humidity?

 

[zak77]

Sounds like the closet walls are getting cold enough to condense water out of the indoor air. If it's just started this year have you done anything to raise indoor humidity?

No this isnt the first year experiencing this. I really dont want to add foam board over drywall without knowing that it wont cause issues and it will solve the condensation issue. Leaving the closet door open with a fan blowing in solves the problem. I'm much more inclined to try the "level to level" fan to keep air moving before adding foam board to the walls.

 

[Kaizen]

I would not add any material in there. Put a duct booster fan in the basement to **** or blow. The other vent will help circulate.
Don’t assume the whole closet is good just from poking one hole. I’d rip it all out in summer and either fit out the wall to accept 2x6?insulation or get one of those small 200sq ft spray foam kits. In my house I fit out all exterior walls to 2x6 as I redo the walls.


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[MattT]

No this isnt the first year experiencing this. I really dont want to add foam board over drywall without knowing that it wont cause issues and it will solve the condensation issue. Leaving the closet door open with a fan blowing in solves the problem. I'm much more inclined to try the "level to level" fan to keep air moving before adding foam board to the walls.

I reckon you risk hiding the problem rather than fixing it by adding foam and drywall. Installing a fan to get heat and air movement into the closet is certainly the safer option.

Personally I'd also check the indoor humidity level. If it's too high you might have condensation forming in other cold spots too.

 

[yeldogt]

Your wall is simply dropping under the dew point of the space. Clothing/ fabric/leather/ actually holds water .. it's normal for a closet to be a higher humidity.

Do you tend to keep the house on the cold side? Gloss paint -- or many coats of paint?

Keeping the door open will obviously allow excess moisture to escape and warm the room.

Unless insulation is missing or there is some hole to the outside -- I don't see opening up the wall doing any good.

You could always cover the the walls with a commercial thin cedar closet product -- this will drop the surface temp of the wall -- also wood is able to receive and give off moisture w/o issues.

 

[strutaeng]

I don't see a problem. You'll add a continuous layer of R5 with XPS, eliminating any thermal bridging from the studs and XPS acts a vapor barrier. Use the tongue and groove panels or use tyvek tape at the seams.

The newest building codes actually require R5 continous rigid insulation for 2x4 studs for most climates.

I did something similar to a closet at my detached garage. I had 2 steel pipes proud of the studs and used 1" XPS to fur out and get better insulation on the 2 exterior corner walls.

 

[James-W]

I am not sure if this is the best idea or not, but I think if it were my house, first off I would rip out the drywall in the closet. Then I would have someone come in and spray foam the full three and a half inches between the studs. Then I would have a hot air duct and a return put in the closet.

My thinking is this. You obviously have a problem of some sort that needs to be addressed. If the condensation continues, depending on how bad it gets, you will end up with soggy drywall, and very likely a bunch of mold. Sometimes you just have to bite the bullet even though it may be expensive.

Anyway, that is my suggestion, others will probably disagree.

 

[zak77]

I'm taking a first step by installing a floor register booster fan to pull air from the bedroom, through the closet and move it to the basement. I'll see where that takes me. I really do not want to do any half-assed fixes to this issue since i dont want to fix things multiple times. Of course just by moving air it isnt exactly curing the actual problem. In a perfect world i would tear out drywall then spray foam the wall but what's holding me back right now from doing anything too crazy is that at some point i'd like to turn that closet into a walk-in shower since the bathroom abuts the closet with a standard fiberglass tub/shower so it'd be a nice upgrade to remove the shower and wall separating the bath and closet to make space for a double sink and walk-in shower. At that point it'd obviously address this issue the proper way since i'd gut the space anyways. But i just need to money tree to grow a little bigger.