Musty Basement Smell and Mold in Toledo

Why does my basement smell musty?

Because something down there is staying damp. That musty smell is usually from mold or mildew growing on materials that stay wet: cardboard boxes, carpet, drywall, wood framing, or the dust on a cool wall. Mold needs moisture. Take away the moisture and you take away what it needs to grow.

In Toledo, basement moisture usually comes from one of these:

• Groundwater seeping through walls or the wall-floor joint, common in the city's slow-draining lake clay
• Humid summer air condensing on cool basement walls and pipes
• A past flood or leak that was never fully dried
• A dryer vented into the basement, or no exhaust from a basement bathroom
• An open sump pit releasing damp air

Is it seepage or condensation?

Do the foil test. Tape a one-foot square of plastic wrap or aluminum foil to the wall, seal all four edges, and leave it about 24 hours.

• Wet on the wall side: water is coming through the wall. That is a waterproofing problem; see interior drain tile or foundation cracks.
• Wet on the room side: humid air is condensing on a cold wall. That is a dehumidifying and air-sealing problem.
• Both: fix the seepage first, then the humidity.

What is the white crust on my basement walls?

That is usually efflorescence: mineral salts left behind when water moves through concrete or block and evaporates. It is not mold, but it is proof that water is moving through the wall. Brush it off, and treat the source of the water.

Can I clean basement mold myself?

Sometimes. The U.S. EPA says that if the moldy area is less than about 10 square feet, roughly a 3 foot by 3 foot patch, you can handle it yourself in most cases. Larger areas, mold in the heating and cooling system, or mold after a sewage backup are jobs for professionals. The EPA specifically recommends a professional with experience in contaminated water if the damage came from sewage.

If you are cleaning a small area:

• Wear gloves, goggles and an N-95 respirator, as the CDC recommends for mold cleanup.
• Scrub hard surfaces with detergent and water, and dry them completely.
• Never mix bleach with ammonia or any other cleaner.
• Absorbent materials such as ceiling tiles and carpet may have to be thrown away if they are moldy, the EPA notes, because mold can grow into the spaces inside them.
• Fix the moisture source, or the mold will come back.

How do I keep a Toledo basement dry?

1. Fix any liquid water first. Gutters, downspouts, grading, cracks, drain tile or a sump pump; see the Toledo guide.
2. Run a dehumidifier sized for the space, with a hose to a drain or the sump pit so it runs continuously instead of filling a bucket.
3. Cover the sump pit with a sealed lid.
4. Get stored items off the floor and out of cardboard. Use plastic bins and metal shelving.
5. Vent the dryer outside and add exhaust to any basement bathroom.
6. Dry anything wet within a day or two. The EPA says to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth.
7. Insulate cold water pipes that sweat in summer.

Do I need a vapor barrier or encapsulation?

In basements with crawl spaces, or on walls that stay damp from condensation, a vapor barrier can help. This Old House lists vapor barriers at about $1,500 to $3,000 for full coverage as a general national range. A barrier is not a fix for liquid water coming through a wall; do that first.

When should I call someone?

• The smell remains after you have dried the space and run a dehumidifier for a few weeks
• Mold covers more than about 10 square feet
• Water comes in after rain, or you see it at the wall-floor joint
• Drywall or carpet stayed wet after a flood or leak
• The moisture came from a sewer backup

Call (419) 515-4608 and press 2 for a local waterproofing company, or press 1 if there is standing water right now.