I just bought a house that was built in the 90s, and I've been keeping an eye on the humidity in the crawlspace. It's reading over 90% on my hygrometer! I've had three crawlspace experts look at it. One suggested a full encapsulation along with a French drain for about $20k. Another just recommended a dehumidifier, and the last said to seal the vents tighter, close off the space under the porch, and also install a dehumidifier. However, since there's no mold present, I'm wondering if it's reasonable to just monitor the situation and only take action if mold starts to appear. The crawlspace does have a vapor barrier too.
3 Answers
Are there any vents in your crawlspace?
Those humidity readings might just be peaks during a hot, humid day. Make sure your crawlspace has a plastic cover over the ground, as that’s key to reducing moisture. If you still struggle with humidity, sealing the vents and adding a dehumidifier is a solid approach. Just remember, full encapsulation should be a last resort if nothing else works.
I had a similar issue with my crawlspace. I installed a dehumidifier and my humidity dropped to 55%. I do have a plastic barrier, but some dirt was still exposed, so encapsulation is on my to-do list. A dehumidifier might just be the simpler fix for now.
Yeah, all the vents are closed.