05:40PM | 09/21/03
Member Since: 09/20/03
2 lifetime posts

We have a crawl space in our basement that has a vent... basically a rectangular hole with a grille over it. Is this something we can permanent seal up? Is it necessary to have or needed by code? It is making it difficult to control the humidity and is causing mold growth. We haven't used a dehumidifier yet, because we figured what's the use with hole in the wall letting in humid air. I am concerned about the musty, mildewy and mold that I smell and see. I am having paranoid vision of what is lingering behind the drywall and plywood walls.
We really would like to get control of the situation... any suggestions would be greatly appreciated.


04:05AM | 09/22/03
Member Since: 06/06/03
1250 lifetime posts
Hello Hope,

There was a very interesting post a couple months back on this topic. I tried a couple basic searches and couldn't find it right off. It referenced a web site which explained, as I recall (please doublecheck!), why one needs to open crawlspace vents in winter and close in summer.

This was definitely contrary to what I had previously thought (in my climate, we worry about freezing pipes!), but it may be worth a couple searches on your own to try and find. Also, if I happen to find it I will re-post...good luck.



10:03AM | 09/22/03
Member Since: 09/16/02
251 lifetime posts
I know which post you're talking about K2. I couldn't find it either. Is this a partial crawl space. If it is I will ask the same questions I always ask.
1. Do you have excessive moisture in the crawl space? If so, do you have gutters and is the land sloped away from your house?
2. Is there a vapor barrier?
3. Are there vents to the outside?
Let me know and I will post again.


10:07AM | 09/22/03
Member Since: 09/16/02
251 lifetime posts
I found it. This was found on page 2 of this category.

Homebild wrote:

You have things 'backasswards'.
In warm humid climates such as Virginia, you need to keep foundation vents CLOSED IN SUMMER and OPEN IN WINTER!

Closed in summer to prevent warmer, moister air from entering a cooler crawlspace and condensing...

Open in winter to allow warmer, moister air to LEAVE a crawlspace and prevent condensing...

No kidding....

Someone gave you VERY BAD advice....

[This message has been edited by homebild (edited August 12, 2003).]


10:15AM | 09/22/03
Member Since: 06/06/03
1250 lifetime posts
Hey there Devildog! (And Hope, of course!)

AHA! Found it! (It's been driving me crazy, looking for it!)

In case you can't open the above, the link it refers to is:



03:56PM | 09/22/03
Member Since: 09/20/03
2 lifetime posts
Hey there...

Answers to your questions:
1. The slope of the land and gutters are fine.
2. I don't think there is a vapor barrier
3. The vent is to the outside..,. which I believe is my main problem. I've seen a puddle on the floor, when it's rain a lot.

In our old house we had the basement finished and a "Humidex" installed. It is basically a dehumifier which vents out with a fan. I am talking to the company to figure out a solution... will let you know what I find out.

Thanks a bunch!!


10:55AM | 09/23/03
Member Since: 09/16/02
251 lifetime posts
I wouldn't spend a ton of money on this. I don't know how much a Humedix is, but a professional inspector told me that he recommends putting a vapor barrier down. Vapor barrier comes on a roll and can be bought in different widths. Try to get one piece to cover the entire crawl space. To hold it down good put 2x4's on top of the plastic. Then stick a dehumidifier down there and close all vents. This allows the dehumidifier to do the work of the vents. I guess I would ask the professionals why this wouldn't work.

Where is the vent that you have a puddle on the floor? Maybe you need to replace the vent with a new one. Does it have a window well? If so, does the window well have a drain? If so, is it plugged? Maybe you need covers for the window wells.

Hope this helps.

Click_to_reply_button Inspiration_banner


Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.


type the code from the image


Post_new_button or Login_button

Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon