We are trying to find the source of a mildewy odor in our home that we have owned for about a year. We thought we had located the source in the humidifier filter, so replaced that and sprayed bleach and disinfectant deodorizer into all the vents. We have replaced all furnace filters as well. There does not appear to be any moisture coming in from outside the home. The “sniff test” doesn’t reveal a source anywhere throughout the house, but a faint lingering odor exists that is noticeable when you enter the home, and our clothing has picked up the odor as well. Could the odor from the humidifier have been the original source and now the scent remains in the carpet and upholstery? Any suggestions as to how to determine/eliminate the culprit? Thank you!
There are many items to check for here, but basically, you’re looking for old or existing water entry or moisture.
If you have carpeting, I would look underneath it. If the floors have gotten wet and never properly dried out, the padding and/or carpet could easily be molded. Even the tack strips around the perimeter can be the source of the mildew smell. You’ll need to pull up the carpeting, and possibly the padding as well to see, but the bad news is, you will likely need to have a carpet installer put the carpeting back if you didn’t discover that that is source of the problem. If this is the cause, you’ll need new carpeting and padding.
Several years ago we had a similar issue in our basement. Although the carpet surface was dry we discovered that there had been two layers of pad underneath and the bottom pad wasn’t never completely drying out, thus causing the problem.
Also check for any signs of drywall, plaster, or paneling stains. If you find any, this could be showing a source of the smell. To be sure, you’ll have to remove an area to find out.
A bathroom shower area can easily be the source of mildew if water is getting behind the tiles. If you find the walls give a little when you push on them, you’ve got a problem. Or, if there is a lower floor ceiling under the bath, you might see water staining.
At the very least, you might consider purchasing and running a dehumidifier. This won’t cost that much and having it run for a few days will likely take the smell out of the air. You’ll have to empty the water frequently, but it can really make a difference. While you’re running the dehumidifier, you may want to turn the humidifier off, as they both do the opposite things. Once the smell is gone, try turning off the dehumidifier to see if the smell comes back. If so, you’ve got to continue finding the source.
If you still can’t find the source, you may want to contact an inspector or company that uses a device to test for moisture. They may be able to help pinpoint the source.
Be sure that you’re not confusing the mildew smell with that of sewer gas, as this could be a different set of solutions.
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