Latest Discussions : Basement & Foundation


12:27PM | 09/04/13
I hope someone can help me with a problem that I am having.

I live in southwest Georgia. It is often humid in this area. My house is about 2000 sq.ft. and there is a crawl space under the house. The house was built during the late 70's. We have open vents around the perimeter of the crawl space and we also have a rather old plastic vapor barrier. I do not have a problem with water seeping into the crawl space as a result of flood or rain. I have a moisture problem presently under the house which appears to be due to a slow dripping water pipe. I will have this resolved next week. However, my HVAC repair person did tell me that he thought the insulation on the HVAC ductwork may need to be replaced because he had seen condensation on the outside of the ducts during this hot/wet summer we have been having.

My pest control company recommends that I install a new vapor barrier, encapsulate the crawl space, install a wireless humidity sensor and install a dehumidifier. The cost is about $2200, plus an annual $100 fee for maintenance of same.

I have three (3) questions:

1. Since I believe that the main cause for the increased humidity in the crawl space to be the leaking water pipe, would it be just about as effective if I did everything BUT purchase/install the dehumidifier? I could use the wireless sensor to indicate if another leak problem occurs under the house.

2. I have read that encapsulating/dehumidifying the crawl space can save as much as 20% in your HVAC bill annually. That sounds very high to me ....... do you know or know of what others have experienced in savings after they have installed a dehumidification system under their house?

3. The pest control company indicated that I have some puddling of water under the house as a result of the water leak drip, outside of a bucket and a sponge ….. is there an easy way to get rid of this puddling after I have the pipe repaired?

Thanks ever so much for anyone who can help with this issue.

Jim Kempf
Leesburg, GA


02:26PM | 01/25/14
Outside rainwater run off should be diverted away from the crawlspace, then plumbing leaks repaired, then the crawl space should be sealed and a dehumidifier and remote humidity sensor should be placed in the crawlspace.

We do all building testing and upgrades for comfort, indoor air quality, durability energy efficiency HVAC, and solar energy in SW Georgia and Alabama.

Duane, Moderator

10:06PM | 01/26/14
Member Since: 11/14/13
90 lifetime posts
Thanks for your question, to begin it is in my opinion and many others that vented crawl spaces especially in the southeastern climate zone should be sealed, foundation vents closed and sealed and at least 8 mil or greater vapor barrier. There are several types of dehumidifiers on the market, what type you use will depend on the size and configuration of the crawl space. If you have a large ranch with a H style floor plan it is possible you could need 2 dehumidifiers, if you have a standard rectangular style you will be ok with 1.
My personal preference is the April aire ducted 70 pint per day unit, It uses uninsulated 8" metal duct for the supply and return, when properly installed this will create a good about of circulation of air under the house preventing stagnate air pockets that form on opposite areas from the small free standing units. I also recommend to remove any glass insulation and have it replaced with spray foam, this will not only insulate it will seal the small holes, cracks and joints that allow air to leak into your living area of the home ( envelope).
Insulating and sealing the crawl door is also recommended. Having a wireless de humidistat is very helpful to make sure you have a proper humidity level.
The price you stated is very competitive.
Conditioned crawl spaces are now accepted by most building codes officials, I always recommend to confirm you are within your local building code requirements.

I hope this helps,
Duane expert moderator.


11:45AM | 08/22/16
Member Since: 06/22/16
2 lifetime posts
Your best bet is to vapor barrier and get a dehumidifier. Your pest control company was right. The vapor barrier saves you so much money because it keeps energy from escaping your home through the crawl space. I would recommend getting a dehumidifier. If it is the cost that is a problem, A smaller dehumidifier would probably work. This one from Seaira Global would probably do the job.


12:27PM | 10/06/16
Member Since: 10/06/16
1 lifetime posts
We here at ATMOX believe that a sealed crawlspace still needs to be ventilated at certain times. We are the industry leaders in crawlspace and attic ventilation. We encourage you to visit our website and see for yourself why if you're going to encapsulate you should still maintain some form of ventilation, especially in dead corners. We have dead space fans, intake exhaust fans, controllers and much more to assist our installers around the world.


11:06AM | 08/11/21
you never mention what the humidity should be under a house...i have encapsulation and dehumidifier and sump pump...what should I read on the thermometer they gave me for under the house

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