How to Air out a Musty Basement or Cellar

Older homes and even new ones can encounter some moisture problems. Here’s what you can do to fix them.


Especially in rainier months, older homes and even newer ones can encounter some moisture problems. Here’s what you can do to fix them.

Q: We live in an 1850s house with a stone cellar that has a sump pump. It’s often damp down there after heavy rains, but this summer has been very wet, and we had a flood during a hurricane. Even though the cellar seems dry now, there’s a musty smell. Could this be mold? Is it harmful? What should we do? — J.T., Harrison.

A: Mold spores are present in the atmosphere all the time, and only need moisture to multiply. Problems occur when abnormally high quantities gather — and a damp cellar is party central for mold. “Yes, the musty smell is probably from mold,” agrees Natasha Casparro of H&H Environmental Construction and Consulting, the Ulster County–based mold-removal specialists who serve all of Westchester County ( If you can see green, black, or white spots on the cellar walls or floor, or on anything you have stored down there—that’s mold. “Even if you can’t see it, it could be there,” says Casparro. “No mold is good mold,” she goes on. “It’s not good to breathe. If you have any respiratory issues, you can feel it.”

Controlling the moisture is the most important step to take, Casparro says. A dehumidifier should do the trick and keep mold from growing, but it won’t cure a problem you already have. Although there are websites that suggest you can remove mold by washing down the walls with soapy water, Casparro says that that really only applies to small areas, like the tile in a bathroom. Even then, if you have asthma, allergies, emphysema, or a weak immune system, it would be best to have somebody else do the clean-up. “Soap removes mold, but doesn’t kill it,” she says, and neither does bleach. “When you start washing down walls, it’s not visible any more, but it becomes airborne. We would contain the room that the mold’s located in, and wear a hazmat suit and masks. You really need to wear proper attire.” Even dead spores can cause a reaction in those who are sensitive.

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H&H uses a non-toxic chemical called Anabec to scrub walls and floors. “Then we use a spray to treat and seal the surfaces so the mold won’t come back — and we back that with a 30-year guarantee,” says Casparro, adding that the sealant is also environmentally friendly. You’d have to discard any porous materials that smell musty, although items with hard surfaces can be cleaned.

“Before we do anything, we go in and see how to correct the problem,” Casparro says. Estimates are free, and the work usually takes a day. Casparro also suggests you get an air quality test to detect unusually high amounts of spores. But I’d say that, if musty equals mold, you could spare yourself that expense and just organize its removal. You’ll find all kinds of info and tips on H&H’s website.


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