If your basement is already beginning to smell musty, and usually starts to every spring, here’s what to do about it.
First understand that musty odors mean fungal growth.
Fungi like to grow where it’s dark, damp and undisturbed.
That describes the lower levels of plenty of homes during the summer.
Besides being unpleasant, mold and mildew can cause health problems, especially for people allergic to the spores.
When it gets cold, below 50 degrees, most molds and mildew go dormant, and the same is true if their environment dries up.
That’s why the basement seems musty in the spring and summer, but not in the winter.
Clean. Wash surfaces with a detergent water solution.
If you see signs of mold or mildew, treat with a solution of 1 cup chlorine bleach to a gallon of water. A spray bottle works well for corners and small areas. Bigger areas require a bucket and sponge or brush.
Apply the solution, wait about a minute and wipe off. Rinse and wipe dry and move on to the next area. Start from the top and work down. Always be sure to test the solution in an inconspicuous area first to make sure it’s safe and won’t lift colors or harm surfaces. Mitigate. Sunlight kills mold and mildew. Pull whatever you can out into the sun as temperatures allow. This is especially effective on breezy days with low humidity. Vacuum upholstered furniture thoroughly outdoors and dispose of the vacuum bag immediately to keep from scattering spores the next time you vacuum.
Prevent. Once mildew is removed to the best of your ability, change conditions in your basement:
Keep outdoor moisture out. That’s snow melt, rain, etc. Be sure gutters and down spouts are in good condition and deposit water at least 10 feet from the house’s foundation. Ensure that the soil (not just the landscape rock or mulch) slopes away from the house. Even if the basement doesn’t leak, concrete easily transports moisture in the form of vapor from soggy soil to the basement air, increasing humidity and mold-growth opportunities.
Operate a dehumidifier. If you can add the ventilation and dehumidification of an air conditioner, that will help too.