LESLIE: Okey-dokes, we’ve got Paul in North Carolina who’s got a crawlspace question. What can we do for you today?
Reduce Moisture in your Crawlspace
PAUL: Yes, I have a crawlspace and I’m curious to know what the best way to seal it is. I’ve been told that I have a moisture content of between 25 and 30 percent.
PAUL: It’s a pretty – it’s a walk-in crawlspace and I’ve got vents all over the place but I would just like some of your advice.
TOM: Alright, couple of things. First of all, we want to take every step that we can to reduce the amount of moisture inside the crawlspace and …
LESLIE: By working outside.
TOM: Yep. Go ahead. Yeah, exactly.
LESLIE: Yeah, you want to make sure that you’ve got sufficient gutters and downspouts on your house and if you don’t have gutters, get them; if you’ve got them, make sure that they’re clean. Also with the downspouts; people forget to snake the downspout and if the downspout is clogged up, it’s not going to do its job for you. So make sure everything is clean and free-flowing.
Then you want to look at where those downspouts deposit the water. Chances are it’s just dropping all that rainfall right next to the foundation. So you want to make sure that, if you can, extend that downspout three feet, six feet, whatever you can do, away from the house so it gets away from the foundation wall.
Then you want to look at your grading; you know, all of the soil around the property. Make sure that it slopes away from the house. You want to go about six inches over four feet so it’s not very drastic. You just want it to gently slope away. Just move all that water away from the house. This way, you’ll keep it dry and then you can cover that floor with viscuine.
TOM: That’s right.
PAUL: OK. And I do have the viscuine on now and I really have a pretty good slope and everything. The concerns I have are if I’m going to go ahead and seal it, can I just plug up the vents with a urethane kind of thing or a sheathing and have the viscuine on the floors or do I have to encapsulate the walls, too?
TOM: Well, let me give you one more thing that you can try before you take this dramatic step and go to a completely-sealed crawlspace. And that is that you could get some fans that are – there are fans that are designed to fit into the same space that you have the crawlspace vents now – they’re 8×16 – and you wire those to a humidistat. So whenever the humidity comes up in the crawlspace, these fans will come on. You’ll probably have two or three of them.
PAUL: Oh. Oh, that’s a good idea; as opposed to – Tom, as opposed to a dehumidifier?
TOM: Correct. And when the humidity comes up and the fans kick on, it will draw drier air from the outside through that space.
PAUL: OK. Alright, well all of that makes sense and I have done a lot of diligent work on this. I’m a real estate agent and I’ve had home inspectors over here looking at it.
PAUL: But I don’t like 25 percent moisture in there, so …
TOM: No, it’s too wet because when the moisture gets above 25 percent, the decay organisms in the lumber start to wake up and you can get some structural damage.
PAUL: (overlapping voices) You bet.
TOM: I would try the fans before I go through the trouble of sealing the entire space.
PAUL: OK. And we are on a well and septic and we get a lot of condensation in the – coming off the pipes; the water pipes from the …
TOM: Well, insulate them.
PAUL: Oh, OK. Alright.
TOM: Insulate them.
PAUL: Hey, you guys have been great. I listen to you all the time.
PAUL: Thanks a lot.
TOM: Glad that helps you out. Thanks so much for calling us at 1-888-MONEY-PIT.