Moisture level in Crawlspace

[Danny O'Donovan]

Is anyone aware of the "allowed" moisture level in a vented crawlspace in North Carolina? I would appreciate a reply as soon as someone is available. I have not been measuring a moisture level. Thank you.

[Scott Patterson]

Is anyone aware of the "allowed" moisture level in a vented crawlspace in North Carolina? I would appreciate a reply as soon as someone is available. I have not been measuring a moisture level. Thank you.

I don't know why you would be measuring moisture levels unless your thought it was a problem.

A few questions about what type of moisture levels:

Wood?

Concrete?

The ground?

RH of the air?

[Jerry Peck]

RH of the air?


My guess would be the RH of the air, which should be close to, and probably slightly more than, the air outside the crawlspace (unless it was raining or has recently rained, in which case the air outside the crawlspace probably has a higher RH.

Now, if there is a moisture related problem, then regardless of what it is, it is "too high", the solution would be to find the cause the make corrections based on that.

[Danny O'Donovan]

Thank you. It is the RH that is being measured and the stat is set at 50 and will turn off when adjusted to 65. I am suspicious that there was a "previous problem". The ground under the vapor barrier is completely dry and there is no sign of any moisture on the wood framing.

[Jerry Peck]

It is the RH that is being measured and the stat is set at 50 and will turn off when adjusted to 65.


You have a dehumidifier in the crawl space?

[Danny O'Donovan]

No, Jerry.

[Daniel Leung]

The ground under the vapor barrier is completely dry and there is no sign of any moisture on the wood framing.

Danny, if dry and no sign of moisture that means no existing problems, we cannot trace back the history. Then check any vents.

When you see the case as shown in my photos, that is a problem.

[Jerry Peck]

It is the RH that is being measured and the stat is set at 50 and will turn off when adjusted to 65.


You have a dehumidifier in the crawl space?


No, Jerry.


Danny,

Now I am really confused.

What humidistat on what turns off when adjusted to 65?

[Gunnar Alquist]

You are not being real clear. I am guessing there is a humidistat controlled ventilation system. Difficult to offer help when the information provided is incomplete.

[Scott Patterson]

Try this website. They have a great amount of information on crawl space environments. They are out of NC.

Advanced Energy (http://www.advancedenergy.org/buildings/knowledge_library/crawl_spaces/)

[Danny O'Donovan]

Thanks to everyone. I appreciate the help. Thanks especially to Scott for the link to the website. It is invaluable. Danny.