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Community and Q&A

Where’s the smell coming from?

detlas | Posted in GBA Pro Help on

A musty, mildew smell emanates from 2 bedroom closets in the front of our single story 13± year old house every time it rains since we bought it 2 years ago (and before us no doubt)…but nowhere else in the house.

After the last rain, I smelled the musty odor coming from an electrical outlet right under a front window beside one of the closets as well. I’ve had several professionals here trying to figure out what’s causing it…they found no evidence of moisture [used a meter to measure] in the closets’ interior drywall, wood or carpeting nor any signs of leaks in the roof when in the attic; I even thought it was solved when it was discovered that a sewer line through the foundation wall wasn’t sealed, so water was getting under that part of the house where the smell was prevalent.

After having it sealed & the crawl space conditioned and a dehumidifier installed, the smell’s still evident in the 2 closets after it rains (the crawl space is @ 47% humidity and no longer smells musty).

The house has vinyl siding on all but the front, which is bricked. It appears that the bricks under the windows are properly angled to allow rain to flow away from them. Also, I had everything checked under the soffits and sealed the area where the garage meets the front at a 90° angle (that helped one area, but not all). I even had all the exterior windows and doors recaulked. The only 2 possibilities left to my way of thinking are (1) water’s getting behind the bricks somehow [I contacted the reputable builder who said it can’t be the brick causing it…he did not remove any bricks to check though] or (2) the fact that the build-up of mulch over the years prior to us is against the brick foundation so high that it’s right up to the bottom edge of the sealed crawl space vents (so maybe moisture or just the musty smell is being wicked up somehow in the caviaty between the vapor barrier and the plywood exterior?).

I certainly don’t want to tear off the bricks only to find that it’s not that. Also, am trying to avoid putting a hole in the closet drywall.

Any suggestions?
Exasperated Sal

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  1. GBA Editor
    Martin Holladay | | #1

    1. It is a certainty that rain gets through brick veneer. This is easily demonstrated with a garden hose, if you want to run the experiment -- all you have to do is open up a wall on the inside, to see what happens when a garden hose is sprayed on brick veneer.

    2. The way that we handle all the rainwater that gets past brick veneer is that we install flashing systems where needed; we maintain an air gap that allows water to flow to the bottom of the wall; and we collect the water at the bottom of the wall and install flashing that directs the water to weep holes.

    3. If the systems I described above were properly installed in your brick veneer walls, and if those systems are still in good shape, there is no reason to believe that your walls have any moisture problems, and no reason for your closets to smell musty (at least no reason connected with your brick veneer).

    4. Your wall could be defective if (a) mortar is clogging the air space behind the brick veneer; (b) the flashing systems are absent or poorly installed; or (c) the weep holes at the bottom of the wall are blocked by mulch.

    5. If you want to see how damp your wall sheathing is, you should cut an inspection hole in the drywall of a closet where you notice the smell and see what's going on.

  2. detlas | | #2

    Thanks for your quick response, Martin. I'm 1st going to assume (more like "hope") the problem is blocked weep holes, since the mulch is so high & correct that issue next. Wish me luck!

  3. GBA Editor
    Martin Holladay | | #3

    If blocked weep holes are part of the problem, it still may take quite a while for your damp wall sheathing to dry out.

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