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Get Rid of a Moldy Smell From Your Crawlspace

  • Transcript

    LESLIE: In Rhode Island, Susan listens to The Money Pit on WPRO. And you’ve got a smelly problem. What’s going on, Susan?

    SUSAN: Hi, how are you?

    LESLIE: Good, how are you?

    SUSAN: Yes, we built a home about 28 years ago. And we added an addition on – it’s been like, say, 22 years. So, we have a crawl space in the addition. And the crawl space is insulated but it is a dirt floor. And we have polyurethane – urethylene – polyurethane down. But I still smell – tend to smell … around the summertime we have a dehumidifier running in the cellar. And I notice, in the summertime, I still smell that, like a moldy …

    LESLIE: Like a moldy moisture.

    SUSAN: … moisture smell.

    TOM: The best thing for you to do is to try to take all the steps necessary to reduce moisture at the foundation perimeter. So that would include, for example, looking at the grading and making sure that slopes away. And also, look at …

    LESLIE: At your gutter system.

    TOM: Yeah.

    LESLIE: Do you have gutters on the house?

    SUSAN: (inaudible) we have a grading going … on all sides it goes … we’ve got a gutter on every corner and we’ve got the grading goes … slopes down to the backyard.

    TOM: Well, what about the gutters? Are the downspouts discharging away from the house?

    SUSAN: Yes. We have a … I have like little … the little pieces that go out like when the drainpipe comes down.

    LESLIE: It’s like a little concrete fan.

    TOM: Yeah. How far does the water from the gutters discharge from the house?

    LESLIE: (overlapping) Those are short.

    SUSAN: A foot?

    TOM: That’s not enough.

    LESLIE: Yeah, they need to be further away from the house.

    TOM: Yeah, not nearly enough. Yeah, you want to go out … if you have a moisture issue, you want to go out three or four feet. So what you want to do is have the downspout go out and have a piece of downspout material go about two feet. And then you push the splash block out about to the edge of that; so that’s like another two feet long. So by the time the water gets to the ground, it’s about four feet away from the house.

    LESLIE: Well, and also, if you don’t want to see the downspout running away from your house on top of the ground, she can bury that under the ground, can’t she?

    TOM: Yeah, she can run it under … underground with solid PVC pipe and bring that pipe around and out somewhere. Especially if you have a good slope away; you could have it break out to daylight somewhere else. But if those downspouts are only dropping a foot from the house, that’s just going to be flushing lots of moisture into that crawl space area. Those are two things you can do right away.

    And then, in terms of the vapor barrier, I think you’re talking about polyethylene; the plastic sheeting.

    SUSAN: Mm-hmm.

    TOM: You want to have that across the entire dirt floor and have as few seams as possible. And the last thing you can do, you mentioned that you have a dehumidifier. Do you have any exhaust fans in that crawl space?

    SUSAN: No.

    TOM: Well, what you could do is … there are exhaust fans that are designed to fit inside the space that an 8 by 16 concrete block would take up; in the vent space of the crawl space. And you have those wired not to a thermostat, but to a humidistat. So that whenever the moisture gets high in the crawl space area, the fans will kick on and pull dry air right through that space and dry it out.

    SUSAN: Oh.

    TOM: Okay?

    SUSAN: I never heard of those.

    TOM: Yeah, well, that’s just another way to do it. You get a crawl space – vent fan for the crawl space vent – and you hook it up to a humidistat. That comes on when it’s … when it gets moist, okay? Not when it gets hot or cold.

    SUSAN: Okay. Because we have little vents that are in … around that …

    TOM: Exactly. And they fit in that space. They’re designed to fit exactly in that space, Susan, and that’s what’s going to help dry it out. So it’s not just one thing. It’s not a miracle cure, you know? You don’t just put one product down. It’s a bunch of little things. It’s the grading; it’s the gutters; and it’s the ventilation in that space. Okay?

    SUSAN: Well, that’s the thing. Because I’d like to … I’d like to store things in there, too …

    TOM: Sure.

    SUSAN: … and I don’t like the idea. And I also … my husband put a fan there at that opening and hoped that that’ll help through the summer. I don’t find it in the winter but I find it in the summer.

    TOM: Yeah. Think of it as a system. It’s a bunch of things that work together to keep the space dry.

    SUSAN: Alright. Well, thank you very much.

    TOM: You’re very welcome. Thanks so much for calling us at 1-888-MONEY-PIT.

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