Musty Smells in Sheds and Garages

A musty smell might be described as earthy, moldy, stale, or dank. Of course not everyone has the same smell descriptors (and not everything can be described as dank), but I think we can all agree that for the most part, a musty smell is not a good thing.

At some point or another, we all want to get rid of a musty smell that we detect.  If you’ve ever been an older shed or garage, it may smell a bit like this. It is an indicator of decay, a sign of uncleanliness, and it could also be unhealthy. My garage seems to be perennially musty as the spring thaw tends to bring some moisture on to the floor. I have to work to keep that moisture from taking over.mold on wall

When it comes to mustiness, the thing I worry about is that I know some people that live in musty smelling sheds who are just used to it.  they might jokingly say “yeah, my shed has an odor.” Odor conditioning is our mind’s way to deal with strong odors that won’t go away. It might be a blessing in some situations, but with musty scents it seems to be just sad and dangerous to your health. And since we care about our readers, look on to find the best ways to protect your health.

What is Causing the Musty Smell in my Shed or Garage?

First, you have to identify the source. I never advocate simply covering-up a smell without getting to the bottom of where it is coming from.  The smell will be back again and again.

In my years of experience working on sheds and garages, and inheriting a few old structures on properties I have bought, the musty smell is usually coming from a few places:

Moisture issue in the structure

wet garage floor from car snow
Snow on vehicles turns in to water on the garage floor.

Look for moisture issues, especially the kind that never truly dry out. I’m not talking about a spilled bottle of water that evaporates. I’m talking about a leaky roof, unsealed windows, or a chronically wet floor, the kind that is always a little damp.  This absolutely is the biggest culprit of a musty smell.

Wet stuff in the garage

We all bring wet things into our garage at times.  Maybe it is the car full of snow that will heat-up and the snow will turn in to a big pool of water.  Or perhaps you wanted to bring the tarps in from a rainy day so they can dry off.  The water then gets on your garage floor, and pools.

Animal residue (especially in sheds)

Animal residue — be it an old kitty litter, or waste that slipped between the floor cracks in an old chicken coop — has a way of smelling musty.  If you allow animals in your garage orcat litter kitty shed, be sure you are cleaning up after them regularly, and consider sealing the floor.

Plumbing or appliances

Most garages or sheds don’t have plumbing, but some nicer ones certainly do.  Plumbing can leak, and when it does, especially behind a finished wall, it creates a chronic dampness that absolutely can create moisture.  The good news is that many small plumbing leaks can be fixed with just a bit of teflon tape and elbow grease.

Appliances — such as that beer fridge in your garage, can also cause a musty smell if they leak or if the condensation is an issue and not routed to a good drainage spot.

Mold in your garage or shed

This goes hand-in-hand with our first point on moisture, but musty smells could mean you have mold growing somewhere. Mold likes a specific environment: damp, dark, and warm. It can grow in places outside of those parameters, but it thrives, growing quickly in places like a sheet-rock wall which has a leaky pipe dripping onto it. It doesn’t even have to be a leaky pipe, it could just be a cold water pipe in a humid environment causing condensation. One would think that if the leak were obvious you would have noticed it before it gets

water puddle garage
This car snow runoff has gotten many other items wet. A definite musty-smell risk.

musty. Check places you don’t normally go, like behind walls, in crawl spaces, and in the attic. It doesn’t take much of a mold issue to make things unpleasant.

Best Musty Smell Removal Methods for Sheds and Garages

Remove wet and damaged materials from your structure

There are certain materials which you just aren’t going to be able to repair or clean once they have been damaged by moisture and mold. For finished garages, sheetrock tends to expand making it unsightly and a haven for dangerous mold. Fiberboard and chip boards can get warped and begin to decompose. Flooring and the cushioning or liner underneath can get sodden with moisture and become dank smelling pretty quickly. There isn’t a good way to clean and dry carpet that has become musty. Sometimes it’s better to remove everything and start over. Remember to wear protective breathing equipment to avoid the spores and dust. Vacuum when you are done.

Don’t just remove the actual building materials that are wet. If contents of the garage have become wet by being stored under a leaky spot, consider tossing them.  Wet cardboard, in particular, can become musty at an impressive rate.

By the way, if you can avoid putting sheetrock and carpet (or other flooring) in your shed or garage, we suggest avoiding it.  If you need something to cover up the hard concrete floor, just use big rugs.

Clean the area of all mold spores.

Once you’ve removed material damaged by the mold you will be left with bare studs, concrete foundation, or something hard that fended off the moisture. It’s time to do somewash mold cleaning. Cleaning the area will get rid of staining left by the mold, kill any spores still left, and help to reduce musty smells that might still be lingering around the area. While wearing protective gloves and a mask, scrub the area clean with a brush. A good homemade mold remover recipe is: one part boric acid, two parts white vinegar, two parts hydrogen peroxide, and four parts water. Try not to use too much of the cleaner as it will contribute to excess moisture in the area.

Now deodorize and ventilate the area.

When it comes to mustiness, air flow is your friend!  You need the air to be moving around in order to get rid of a musty smell.

Once the area has been scrubbed and excess moisture mopped up, it’s time to really dry it out by adding an airflow. You could set up a box fan or a space heater. Maybe you could plan this around a nice breezy day and open up the windows? Fresh air is going to make things dry faster and smell better. If the odor still persists, you could try scrubbing the area with a baking soda/water paste or try just sprinkling a large amount in an area for a few hours and then vacuum it up later. Whatever you do, don’t repair a damaged wall without letting it dry out first.

Be sure to get rid of the source of the dampness.

Having now removed all of the damaged materials and spent a couple of hours scrubbing and drying the area of mustiness, you are now as aware as anyone of how important being proactive in your shed maintenance can be. The earlier you catch that leak, the sooner you seal that bathtub liner, the faster you insulate that cold water line, the less hassle you’ll have in the long run. It’s all about maintenance. Keep that dehumidifier running, keep those drains from clogging, check your gutters for clogs and direct them away from your foundation. These and a hundred other daily proactive efforts will add up to a much easier time of it for you as a homeowner.

Preventing a Musty Garage from Happening Again

Let’s say you have cleaned-up, and the source of the musty smell seems to be address.  Great!  What are some things you can do to keep your shed or garage from getting musty again?

Fixing the source of the leak

garage floor drain
A garage floor drain can greatly improve moisture issues on a floor.

This one is obvious, but it has to be the first one because it is the most common cause of musty garages and sheds. As noted above, fix the source of the leak, whether that source is from above (roof), below (floor or crawlspace), openings (doors or windows) or internal (plumbing and pipes or appliances).

Garage Floor Drains

This is next-to-impossible to retrofit into an existing garage, but if you are reading this when you are about to build or remodel a garage or shed, consider adding floor drains in the floor.  If your city allows them, a floor drain routes the runoff from vehicles and other things to a drain that goes out to your yard or ties to your sewer.  It gives water a defined path for leaving your garage.

Keep Pets Out

Consider keeping pets out of the garage or shed, if you can, as they just have a way of adding a musty smell to things — especially cats who tend to take care of their business indoors vs. outdoors.seal garage floor urine

Seal the Floor

Sealing a floor can be a good idea if you know that your garage floor likely will experience spills, car runoff, or moisture from time-to-time.  The thing to know about sealing a floor, though, is that you need to do it regularly.  The seal wears off, and every few years you will need to redo the job.  Also know that the water will still be there, it just won’t absorb into the concrete – so be sure you have a plan for getting the water out once it is there.

Garage Mats

Garage mats are a good idea for people who experience leaks or snow runoff from vehicles inside their garage.  The mat catches the moisture, and then you can either wet-vac it up,garage floor mat or drag the mat outdoor periodically to dry it off.  They are an inexpensive way to fix what can be a troubling issue. We like the one from Welkin, here on Amazon.

Musty Smell in Clothes

If your clothes are starting to get a musty smell, it could just be that they have absorbed the smell of wherever you are storing them. Check your closet or dresser for signs of mold growth. If your closet just has a funky odor, consider putting an open box of baking soda inside to absorb and neutralize that musty smell.

Mustiness in clothing could also be caused by you putting your clothes away before they are completely dry, and some mildew is forming on the damp clothes. It could also be that your washing machine has a musty smell and it is transferring to your clothes. Try flushing out your washer by running it extra full of extra hot water with extra bleach. Also adding some baking soda to your everyday wash can help neutralize odors in the machine. For that, you may need a bit of baking soda, so we’d recommend the 4lb box of Arm & Hammer from Amazon.

Finally, some clothing is meant to get wet, such as rain coats, outdoor sports equipment, or even fly fishing waders.  They key with avoiding these clothes getting musty is to let them thoroughly air dry before storing them again.  A little trick – it often helps to turn them inside out.  Often, it is the inside of the clothing that retains that little bit of moisture.

Control Musty Smell in Basements

Temperature control.

Our first parameter is controlling the heat in your basement. Mold thrives in warmer temperatures, especially if it is wet. If you can keep it cooler, the musty smell won’t be as likely to grow. This isn’t going to work if you have someone living in your basement, which means you’ll just have to keep it drier.  That also means making sure that the basement has a consistent temp rather than a yo-yo which can cause a condensation cycle.

Humidity control.

Another parameter to control is our moisture level. As we have discussed, mold requires a certain level of moisture to be viable. It seems like even if there isn’t any mold, there is stillcondensation shed a musty smell if things get humid. It is as if the wetness reactivates the smell. Getting rid of humidity is easy with the use of an air conditioner or a dehumidifier. Something like the Eva-dry at Amazon may work, but you’ll want to probably get something a bit larger if you’re going whole-home instead of closet or bathroom.

Ventilation control.

Air flow is key!

The third parameter to controlling mustiness in your basement is airflow. Proper ventilation and air movement will do a lot to control the first two parameters. One element of mustiness is the stale quality of the air when it hasn’t been moving around much. Vent to the outside if you can, but even just having an oscillating fan blowing can do wonders.

Mold Related Health Risks

There are thousands of different molds out there and I bet they all have a smell which could be described as musty. Some molds are fairly harmless, some can cause allergic reactions or respiratory distress, and some can actually make you so ill you could die. It’s the black mold Stachybotrys chartarum you always hear about in reference to houses and sick building syndrome. Discovery of a black mold problem in your house can lower property value dramatically. Mold remediation, which is hiring someone to remove the mold and clean the area safely, might be your best bet. That black mold can lead to mycotoxicity, sinus infections, asthma attacks, pneumonia, and death. Not something you want to mess around with.

2 thoughts on “Musty Smells in Sheds and Garages”

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