Potential Sources for Mildew Odor in a Bedroom

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Dear Home-Ec 101,
There is a musty / mildew smell in my home, but I’m having issues locating the source of the smell. As far as I can tell, it’s restricted to one bedroom. I’ve examined all of my clothing, removed the air conditioner, checked all of the furniture, and even the air ducts. I’m guessing it might be in the carpet? Any ideas? The mildew smell is driving me crazy, and I’m sure the bleach fumes aren’t great for me either.
Thank you for any and all suggestions help!
Musty in Muncie

mildew in bedroom

Dear Musty in Muncie:

First of all, you are right to not ignore a musty or mildew scent in a home. While the chances are that its cause was rather benign -not thoroughly drying carpeting after cleaning up a pet mess- there are chances that the smell may be your first clue to a more serious problem.

The sniff test is one of the less than fun homeowner chores, but get ready, you’re going to try to find the source of the problem. If you have central AC, turn it off and turn off any fans in the room. What you’re going to do is try to zero in on the source of the smell and we don’t want anything stirring the air, making that more difficult. Enter the room and shut the door.

Begin trying to find the source of the smell by following the mildew. It is likely to be found around sources of moisture.

Check your windows as a potential site for mildew growth.

Sometimes condensation occurs due to temperature differences between indoors and out. If the blinds are never opened this moisture may take a long time to evaporate, especially if the window is on the north side of a home.

Sometimes there is a problem with the flashing around a window that has allowed rain or melting snow or ice to seep down into the walls. If this has occurred, mold may be growing inside your walls.

Remove switch plates and outlet covers.

Is the air trapped in the walls musty? Is the room adjacent to the bathroom, kitchen, or laundry where there may be a hidden, leaky pipe?

Check the HVAC vents.

Sometimes, especially in homes on crawl spaces, it’s possible your ductwork may have a leak. If this is the case, stale or musty odors may be drawn into your home. (We actually had this issue and our only clue was a musty odor in a bathroom; I’m just so thrilled we spent part of the summer air conditioning the crawl space.)

Look up at the ceiling.

Look for any discolorations that may hint at water damage.

Finally, get down on your hands and knees and check the most likely source, your carpeting.

Work your way around the room. If the smell is isolated to a certain spot and you know that there is an ongoing problem exacerbating the situation (a leaky pipe, window, or toilet) then first dry the area thoroughly. A shop vac is great for extracting any water. Then lightly spray the area with a dilute solution of white vinegar (about 50:50) and set up a fan to dry the area thoroughly. If after two applications this has not taken care of the mildew odor, it’s time to ensure that mildew is not growing in the pad or the subflooring. If this is the case, the carpet and pad may have to be patched or replaced (depending on the size of the mold growth).

bedroom and closet cleaning
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If the subflooring also shows signs of mold/mildew growth, it will need to be sanded and sealed to prevent a recurrence.

Home Eccers, have I missed any potential sources of mold/mildew growth in a bedroom?

Send your questions to helpme@home-ec101.com.

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16 thoughts on “Potential Sources for Mildew Odor in a Bedroom”

  1. Change the bed linens, wash with HOT water and vinegar, and thoroughly spray your mattress down with Lysol spray (Heather’s vinegar solution would work too, I’d think). Letting a fan run over it while your linens are washing and drying might be a good idea. In this heat, if you’re not using air conditioning, or only using it some of the time, your nighttime sweat could be wicking into the mattress and if the air is muggy, it may not be drying fully.

  2. My friend’s home partially flooded during Hurricane Ike. She had to remove the carpet in her living room and bedroom closet. When she pulled it up, they discovered mildew & mold underneath the carpet. She had to have a ‘mositure specialist’ come to the house iwth on of those fancy UV thingymabobs to find out where the water came in. It turned out that when her house was built (she bought it brand new) the builder did not insteall the ‘weep holes’ corectly. (I think thats what they are called). So everytime it rained, water was coming in through the corner of her house, running down the wall, and pooling in the carpet. She did not notice the carpet was wet because she had furniture in that spot.

    If you can’t find the source using Heather’s methods above, you might want to hire a professional to come in and do the water penetration analysis to see if there is a ‘hole’ in your house. Usually home inspection companies will do it, and at least in Houston it runs around $500.

  3. Crawl around the edge of the room, checking the baseboards, and pulling back the carpeting to see the tack strips. If you see mildew or flaking paint on the baseboards, or if the tack strip is really rusty or discolored, you have a floor moisture issue. Remember to check the closet(s), too… my son’s room once had an awful mildew smell and I finally traced it to a sports bottle in a backpack in a footlocker at the bottom of his very messy closet. It had leaked and soaked the other contents of the footlocker long enough to sprout a fine crop of stinky spore-producers.

    • How did you sort out the problem of a leaking bottle in your son’s bedroom. I have a growing mildew odor in our bedroom, and I suspect a leaking or spilling water bottle is responsible. My wife takes water bottles to the bedroom and, apparently, keeps them for when she might feel like drinking, which does not happen that often.

  4. Ooh- thought of this after doing a load of teenage boy laundry- check the hamper itself. His room had an awful smell a few years back, and that’s what it turned out to be. That hamper got trashed, and he now has a bag that hangs on a stand and gets washed with his clothes every week (and then clean get delivered back- in the bag, unfolded, to be put away- his drawers proved they never stayed folded, so I took my half hour back!)

  5. hello, I have recently smelled a mildew smell coming from my master bedroom, we do have a bathroom off of our bedroom, but the smell is coming from the bedroom, I have smelled the whole bathroom it is not coming from in there. we do not have carpeting we have tile flooring in the entire house. I have opened every single bureau drawer, smelled every outlet, smelled around the entire perimeter of the base board smelled the whole bed even took off the bedding. I have moved the bed, I went up into the crawl space into the Attic , it looks like brand new, and I don’t smell it up there at all, it looks like brand new wood . so back to the master bedroom, please help, because I am worried for my wife’s and our wellness and safety. thank-you Mike.

    • Maybe this is too little too late, however, I had the same problem in my master bedroom which connects to an adjoining bathroom–separated by a wall. When we first noticed the smell we fogged the entire bedroom with concrobium and a mold fogger. This seemed to correct part of the problem but it was still a faint smell and we could tell that we had not found the source of the problem. We stopped sleeping in the master altogether…

      Fast forward some eight months later, the smell had gotten so strong in the bedroom that I called a plumber. After investigating everything possible, both inside and outside of the house, the plumber cut a hole in the bedroom wall (directly behind what would be the bathtub’s pipes) Lo and behold, a pipe was leaking water and had been leaking for months! He said that the grout where my tub and wall tile meet had eroded and water was getting trapped behind there. The water collected in the tub drains and started leaking through the pipe that was connected, the water from the pipe then leaked under the floor in the master bedroom. The heat under the house, mixed with the leaking water was causing the moisture and the mold growing on the closet wall. Some of the water just sitting under the tub area was the cause of the mildew and the awful odor.

      After he cleaned out the tub drains and resealed the grout the smell in the bedroom disappeared. A week later, and I m still trying to get rid of the smell in the closet. (He did say that it would take some time for the smell to evaporate) Oddly enough, the bathroom NEVER smelled to say that the problem started and was underneath the tub the entire time…

      I was told that because we had faux wood flooring that it was easy for us to pick up on the smell. The plumber stated that tile flooring–like we have in the bathroom–makes it harder to smell the problem.

      Even more, because my water bill had not increased (other than the two mandatory rate hikes that were imposed on us in such a short time period) I would have never thought that there was a water leak.

      If your problem has not been corrected yet, have a plumber cut a square hole in your adjoining wall where the bathtubs pipes would be–I’m sure you’ll find the same problem I had…

      Good Luck

  6. Hi mike. I’ve been having this exact same issue in my home and have not yet been able to determine the cause were you successful in solving your problem? We’ve done everything that we can think of including adding another event in the bedroom. I am simply out of options at this time.

  7. Tea tree oil is the best way to kill mold and fungus there is if you find the source. It’s a natural fungicide. I mix it up in a spray bottle and Spray suspected fungus and mildew. Kills it dead on contact. You can look up a proper mixture ratio by googling.

  8. Hello. I am trying to find the solution to this problem I have with a very strong sweaty smell coming
    from a wall in my bedroom. I moved to this apartment about 8 months ago. When I was moving in my bedroom furniture I noticed the shadow of a headboard on the wall. I assume the people who lived here previously never moved the bed to clean behind the bed and as a consequence bacteria caused by sweat and moist accumulated behind their headboard, moving straight into the wall. I have tried to clean it with Cilit Bang ( wiped it few times during several weeks), Bicarbonate of Soda, I even tried Vinegar and finally had the house painted. I thought that would have been the end of the bad smell. Although it is not as strong as it was before, I can still smell that sweaty smell. I am getting a new bed today and cleaning around the area have noticed that the shade of their headboard is still showing up, although not as dark as it was few months ago, I can only assume that it is the reason why the smell has not disappeared completely. I am a very clean person and this smell is driving me nuts. Can’t believe how some people live and sleep with that smell without doing anything about it. Please can somebody advice what else I can do that could work effectively against this smell ?

  9. Hi,

    I have a musty smell coming from two cupboards in a house that is almost 1 year old. 1 cupboard is under the sink in the butler’s pantry on an internal wall. The other is on an external wall in the kitchen a cupboard away from the sink and pipes.

    We have cement walls.

    I have removed the skirting, have removed all the draws and inspected both areas several times and cannot find the source of either of the problems.

    Any ideas would be greatly appreciated, as the smell is permeating through whatever i put in the cupboard and I am at my wits end!

  10. I have a moldy smell coming in from electrical outlets on an outside wall about 3 feet from a window. No pipes, no visible, water damage on the inside or out. no cracks under or around the window. No damage to the drywall. house is 13 years old.


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