[nbmech]

Hi,
I need some advice for controlling moisture in my crawlspace. I live in Northeast Ohio. Cold dry winters and warm humid summers. I have a 25' x 25' crawlspace with a poured concrete floor. I have R 13 on the sidewalls, with the vents covered, and no insulation between the floor joists. I have hot water heat and no AC. The crawl has a slight to moderate mildew odor and some mold on some stored items. What is the best way to keep the air dry? The access is from a finished area of the basement where I need to run a dehumidifier in the summer. Should I just put another dehumidifier in there for the summer or is it better to open the vents again or some combination?

 

[PropertyDamage]

Please clarify: 1) do you enter the crawl space from the basement and/or is the crawl space in an enclosed area? 2) Is your crawl space under a raised foundation portion of the home or is it part of the baserment? 3) Does the slab have a vapor barrier? What is the height of this area? Could you post a photo showing the crawl space in relation to the basement?

Unless you have a hygrometer (I use Tramex MRH III), you might want to call a restoration vendor to see if they would: 1) come out and check the temperature and relative humidity of the atmosphere in the enclosed area, and 2) use a concrete moisture tester to test the moisture vapor content coming out of the slab.

With no ventilation, the temperature and relative humidity may be too high to create condensation in the atmosphere, and with no where to egress, this could be creating a moldy atmosphere.

If the vapor content coming from the slab is over 3.5 lbs of pressure in a 1000 sf within a 24 hour period, again, you, without proper ventilation, would create an atmosphere of excessive moisture content. The slab can be tested with a concrete moisture meter (I use a Tramex CME4).

The excessive moisture in the atmosphere has to eventually land somewhere. This would be a reason why some of your stored items have a moderate mildew odor.

Let me know if this helps.

 

[Windows on Wash]

Is there any circulation with the conditioned air?

Sounds like you are treating it as a conditioned crawl, but are not giving it any conditioned air.

Are the rim/band joist areas properly sealed and insulated?

 

[dankaufenberg]

Hi,
I need some advice for controlling moisture in my crawlspace. I live in Northeast Ohio. Cold dry winters and warm humid summers. I have a 25' x 25' crawlspace with a poured concrete floor. I have R 13 on the sidewalls, with the vents covered, and no insulation between the floor joists. I have hot water heat and no AC. The crawl has a slight to moderate mildew odor and some mold on some stored items. What is the best way to keep the air dry? The access is from a finished area of the basement where I need to run a dehumidifier in the summer. Should I just put another dehumidifier in there for the summer or is it better to open the vents again or some combination?

Your situation is a little different then mine, but some of the same steps might help.

If there is visual signs of moisture coming through the foundation. You need to consider waterproofing them.

I would say that opening your vents would help a lot. When you get a chance insulate the floor joists to keep your floor warm. Assuming that's why you have the vents closed.

Once I kept moisture from entering my crawlspace and properly vented it. My moisture problems stopped.

I also created a custom 700cfm electric fan that runs on a humidistat set at 60%. It is also on a timer so it only can run in the day. When I first installed it, it ran for about 3 days. Now it only turns on about once every few months for an hour or so.

Also consider looking at your landscaping and gutters to make sure you do not have an abundance of water congregating by your foundation.

Hope that helps, good luck!