If you have a crawl space smell, trying to get rid of it can be quite a challenge. The best way to get rid of a crawl space smell is to find out what is causing the odor and eliminate it. The most likely culprit is water, which can breed mold and mildew. In addition, animals can get into a crawl space and cause odor problems.
The smell of mold or mildew under a house means there is probably a water problem somewhere in your crawl space. You may have water leaking into the space from outside, leaky pipes or excessive humidity. You will need to spend some time in your crawl space to try and pinpoint exactly where the smell is coming from.
Check out the pipes that are exposed, and look for signs of leaking. Look underneath the pipes to see if you can find any water damage. Take a flashlight and look at the wood under the house for signs of rotting, possibly from a leaky bathroom. Investigate around the outside of your house for any type of drainage problems. Check the gutters and downspouts and make sure they are connected and draining properly away from the house.
If you live in an area with a lot of humidity and have a dampness problem, a dehumidifier properly installed can be important in cutting down dampness and helping eliminate the smell in a crawl space. If possible, open up the vents in the crawl space during the summer months to allow fresh air in. If mold is found, a professional should be called in to alleviate the problem and make sure your home is healthy and mold free.
You may find that the dampness is coming directly from the soil. One solution that some homeowners have turned to is installing a vapor barrier between the earth and the home. These systems are varied and your choice largely depends on how much money you are willing to spend to make your crawl space smell better. There are do-it-yourself plastic sheeting type barriers found in many hardware stores, or the more professional encapsulation systems, which can be quite costly to install.
If you find that water is not the problem, animals may be causing your crawl space smell. In the winter, animals may find an entry into your crawl space and set up housekeeping, chewing up insulation, gnawing on wires, and making a mess of your space. If you see signs that animals have been there, an exterminator or animal control person may be needed to evict them and block off their entry into the space to make sure they don't come back.
Once you have gotten rid of your crawl space smell, your work isn't quite over yet. Remember to check on the crawl space occasionally for signs of returning dampness or animals. It may take a bit of vigilance to make sure that it stays odor free due to changing conditions under your house.