Is it OK to seal off crawl space vents for the winter?

steve22802October 27, 2008

Just wondering if it's OK to seal off crawl space vents for the winter? Or will this lead to dryrot and moisture problems? I'm just trying to find ways to seal my house up a little better and conserve energy.

There used to be all kinds of moisture problems in my crawl space but I installed the vents and put down plastic on the ground and made sure the down spouts were running away from the house. Now it's nice and dry down there but in winter the vents let in a lot of cold air. (The vents are self closing, but the flaps are just thin aluminum.)

Any advice?

- Steve

Thank you for reporting this comment. Undo
lucy

Well, if you close them off, you should make sure you have other ways to let in SOME ventilation, not sealing up all windows, etc., because it's just unhealthy and can even be dangerous (fumes from various things, fireplaces grabbing 02, etc.).

    Bookmark   October 27, 2008 at 8:43PM
Thank you for reporting this comment. Undo
rjoh878646

Close them off. As long as you have a moisture barrier down on the floor of the crawlspace and you are having no moisture problems, you do not need the vents open in the winter. My old house I sealed the crawlspace vents with foamboard cut to fit in the vents from the outside. Did that for 20 years without problems. I always opened it up in the summer as the ground water would come up under the plastic. In the winter it would dry out and I never had any problems. You will notice a difference in your heating bills as the crawlspce will stabilize at ground temperature if you have the exterior walls insulated.

    Bookmark   October 27, 2008 at 9:45PM
Thank you for reporting this comment. Undo
steve22802

Lucy, I'll keep your comments in mind as I do have a wood stove that uses fresh air from inside the house. My house is rather old though so I think there are enough other cracks where some fresh air can get in.

Rjoh, that's exactly what I had in mind. I'll give it a try this winter. I'll keep an eye out for moisture and make sure to remove the barriers in spring again.

    Bookmark   October 28, 2008 at 8:34AM
Thank you for reporting this comment. Undo
billbert

Another thing to keep in mind when sealing off your crawl space is that you are risking Radon exposure. If you seal up the space without ventilation, then any gases in the soil has nowhere to go except through your house. Sealing the soil with plastic tarp and a fun under it is recommended according to the EPA, but I do not know the specifics on installation yet.

Here is the EPA's residential Radon page:
http://www.epa.gov/iaq/radon/pubs/consguid.html

Here is a link that might be useful: EPA & Radon

    Bookmark   October 28, 2008 at 11:54AM
Thank you for reporting this comment. Undo
cciaffone

Not sure where you are, but here in North Carolina
I would never close those crawl-space vents. And yes!,
we do have a moisture barrier down. But this is in
fact Moist Carolina and I want as much ventilation
as I can get, both in the crawl space and in
the attic. I have tried closing both sets of vents
and have spent hours dealing with the result.

    Bookmark   October 29, 2008 at 7:45PM
Thank you for reporting this comment. Undo
rjoh878646

I live in ohio an the house had a double layer of 6 mil plastic down which cut off the moisture in the crawlspace. In the winter when it got below freezing the closed off crawlspace saved me worrying about frozen pipes and saved me money on heating bills. In a addtion my parents put on about 8-9 years ago the crawlspace has been sealed shut from day one. Dy as a bone under there. I was under it a week ago and found a screwdriver I left down there over a year ago. No rust whatsoever, and no moisture. If you live in a climate where it gets below freezing in the winter it is best to seal up the crawlspace.

    Bookmark   October 29, 2008 at 8:26PM
Thank you for reporting this comment. Undo
fandlil

I echo the story about North Carolina. We also keep our vents open year round. We only close off the one very close to the boiler in the winter.

But every climate is different.

    Bookmark   October 30, 2008 at 1:03PM
Thank you for reporting this comment. Undo
kathyg_in_mi

DH all ways closes the vents to the crawl space for the winter. Reopen in the spring! he has some batts of insulation he uses over them after closing the baffles.
Never had water down there! Kathy G in MI

    Bookmark   November 1, 2008 at 8:38PM
Sign Up to comment
More Discussions
What is this stove part called
Found this item in the oven, I know it came from the...
pegasus101
Roofing- Metal or Shingles?
I have to have the roofing done on a house if I am...
ladyvixen84
Need advice for gap under door frame
Hi, We had a contractor install pre-hung interior doors,...
pam27d2001
Need help with shower tiles! Ceramic?
Please help me identify the preexisting tile in my...
shufflehop
Where to purchase Spanish roof tiles? I just need 2 pieces.
One handyman came to my house to evaluate the price...
janesylvia
Sponsored Products
Ray Pendant by Fabbian
$879.30 | Lumens
Matthews Fan Company | Vent-Bettina Ceiling Fan
YLighting
36" Maestro Series Stainless Steel Black Island Range Hood - 600 CFM
Signature Hardware
KOBE Brillia CHX20 Series 30-inch Under Cabinet Range Hood
Overstock.com
Orleans Outdoor Loveseat Cover
$109.50 | FRONTGATE
XtremeAIR 30 Inch Wall Mount Stainless Steel Range Hood PX01-W30
eModern Decor
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™