Crawl Space Dampness

Bradley asks,

About 6 years ago, I had a Termite Inspection reveal that I had high moisture readings in my crawl space. They quoted putting plastic down. My son and I did it ourselves and saved a lot of money and it was a good project for us to work on together. A follow-up inspection yielded a VERY LOW reading. Problem solved!

For about the last year or so I have noticed that the ground (mostly red clay) underneath the plastic is soft. Not muddy, just soft when you put your weight on it. Especially in the middle of the crawl space area. I hope I didn’t introduce another issue with “holding moisture in”.

I have inspection the foundation and piers and do not see any issues with settling, cracks, separation, etc. The crawl space has foundation vents that I leave open year round.

Now my question:

Do I need to do anything to address the “soft ground” under the plastic? Am I introducing an issue with trapping the moisture under the plastic.

THANK YOU – Love your radio show on AM680 in Raleigh, NC.

Our Answer

It’s a matter of degree. If the damp soil yields a bit under your weight, that’s fine and you really don’t need to do anything else.

But if you really sink into it, or if there are actual puddles of water under the vapor barrier, that’s a problem that you should address. First, don’t remove the vapor barrier. You need it down there. If there’s a water problem, you have to eliminate it at the source, not give it a place to evaporate to. Start with your gutters. Ensure that every drop of roof water goes into a gutter, down a downspout, and away from the house – and I don’t mean one or two feet away. Make sure that it goes at least 10′ away. Twenty is better. Next check the grading in your yard. It should slope away from the house in all directions.

Involving your son in these kinds of jobs is a great idea. It’s the kind of think that makes for wonderful memories later in life.

Community Answers

rog

I had the same problem and tried a DIY. I exposed some (10%) of the CS earth, put in a couple of fans to circulate the air and also a house dehumidifier with a built in humidistat and discharge pump. It was $250 or so and ran the discharge tubing outside away from the foundation on the low end. Covered all my vents and put the dehumidifier on a smart switch so I could set up a timed function if I want. I’m in the south so during dry months it really doesn’t run much. So far (2 years), so good.