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ajones33
Basement Foundation Vents
ajones33

I own a home with a finished basement however it also have foundation vents. I am looking to seal these up as I am getting a lot of moister in through them being that I live in Georgia and humidity is extreme. How should I go about sealing them up permanently? I was thinking about cutting the old vents out and putting in cinder block and mortar? Anyone have any suggestions that might be easier. Any suggestions are welcome.

Thanks

-Adam

dj1
Re: Basement Foundation Vents
dj1

What you want to do is a mistake. You need vents. Why do you think builders are required to put them in by code? In fact, you may need more vents than you have.

"I am getting a lot of moister in through them" - when you say moisture, do you mean rain water or humidity?

Try a dehumidifier for a few days, remember to empty it when full, and see if your humidity goes down.

ordjen
Re: Basement Foundation Vents
ordjen

I would disagree with dj1 on this issue. If you have a finished basement and the space is now within the house envelope, subject to the house heating and air-conditioning system, the basement/foundation vents should be sealed.

In my former home of Chicago, where winter's are very cold, the crawlspaces and or basements were sealed from the outside. Not to seal them risked freezing of the plumbing down there. In my present home opf Portland, Oregon, the crawl spaces are vented. However, there is a new movement to retroactively seal and condition them as part of the house envelope. It protects the plumbing and makes for a more comfortable , foot warm living space above.

You can certainly seal them up with mortar and cement block, but that is a lot of work. I see nothing wrong with simple pressure treated wood blocking and foam or other insulation.

sissy
Re: Basement Foundation Vents
sissy

all you need is a good dehumidifier .Sealing vents like said will help keep the moisture out .It was an old out dated way of doing a house and can cause mold problems .You can close them up or put glass block or make them big enough for windows .They still do that with double wides here with a crawl space but are starting to understand that it is not a good way or the right way .I have a dehumidifier in my basement in VA and it empties to out side and works great .I did not want the hassle of emptying it ..I even had 1 in my house in NJ and would never go without 1 .Invest in a good 1 ,but you can buy cheap 1 to try it out and see if it works

ordjen
Re: Basement Foundation Vents
ordjen

If the basement was properly finished off and is heated/cooled by the central heating system, additional dehumidification should not be required. The air recirculating throughout the house will condition that basement too. The assumption is that you have registers and a return in the basement. My first house had a deep basement and the air down there was as comfortable as anywhere else in the house.

garskoci
Re: Basement Foundation Vents
garskoci

A couple things to note. My house is in the Chicago area. We have a multitude of weather here. What type of floor do you have? If you have concrete, you're ahead of the game. I have dirt. So, I sealed off my crawl a year ago. The vents were sealed and also the floor. Someone made a comment that sealing off your vents will only trap the moisture. Which is true. No circulation will trap it in the space. If you seal off the area, it has to be conditioned as a normal room in the house. Heat in the winter. AC in the summer. This keeps the air stable. For me it was easy to do. I have an addition with a basement that opens to the crawlspace. That and some creative venting keeps the space comfortable. You also may have to insulate pipes and or ducts. It all depends on your situation. In extreme cases, you may need a dehumidifier.

Mastercarpentry
Re: Basement Foundation Vents
Mastercarpentry

Garskosi is right, there's more to this than just blocking them off. The general rule of thumb is to seal conditioned spaces and insulate too if necessary, but to ventilate non-conditioned space and to not insulate them unless necessary.

If you've got a hard 'Georgia clay' floor and it stays dry it's probably OK as-is, but if it gets the least bit visibly damp you should pour a slab. Soil basement floors can emit a lot of humidity and closing the ventilation will trap it. If you're in North Georgia you should also have a Radon vent pipe with a concrete slab; the granite geological base in this area is notorious for Radon emission same as it is in upstate SC where I am.

Phil

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