Keep Foundation Vents Open or Closed?
LESLIE: Dennis in North Carolina, you’ve got The Money Pit. What can we help you with today?
DENNIS: In my home, on the foundation, I have about a dozen or 14 foundation vents. They measure 8 inches by 16 inches and they have the capability of being opened or closed.
DENNIS: You know, they have the screen on to prevent bugs from getting in.
TOM: Yeah. Uh-huh, yep.
DENNIS: Now, should they be opened in the summer or closed in the winter or vice versa? I’m unclear.
DENNIS: Maybe you can help me out.
TOM: Yeah, well, the job of the vents is to basically keep the crawlspace area as dry as possible. So here’s what you want to do: in your area, probably for a good 10 months of the year, you’re going to have them open. You can close them in the winter months when it gets really cold and the air is drier; there’s less moisture in it. But for the most part, you want to have the vents open so that the crawlspace can vent.
Now, in addition to that, make sure across the crawlspace floor that you have plastic sheeting. That stops a lot of moisture from wicking up through the floor and getting into that space in the first place. The reason you want the crawlspace dry is because you’re going to avoid mold and also, if you have insulation down there, if you keep it drier, it’s going to work better.
DENNIS: Excellent. That answered my question. Thank you very much.
TOM: You’re welcome, Dennis. Thanks so much for calling us at 888-MONEY-PIT.