Dirt Crawl Spaces- A Housing Epidemic

Besides dry soils causing settling of your floors and high humidity causing mold and rot and all the fun that goes with it, dirt crawl spaces cause other problems, which can be corrected at the same time in one project.

 Let's review this more than significant problem briefly...

Exposed earth under a wood floor. You don't have to be a rocket scientist to figure out that damp earth will contribute moisture into your home. And when the earth dries out, soils can shrink and settle and take the piers that hold up your floor with them.

Groundwater leaks. Often, builders pay little attention to keeping a crawl space dry. (Hey, it's not very deep so it shouldn't leak, right?) so when it rains hard, they leak. And oftentimes, crawl space foundation walls are made from porous hollow block- God's gift to waterproofing contractors. 

Vents. Vents are supposed to let the moisture out. But they don't. The house has a suction at the lower levels as warm air rises in the house. This sucks the air in at all the vents. In winter, you have freezing cold air under your feet! Not so good for the heating bill or comfort. Read on...

Mold. In the summer, the vents let in warm humid air. The crawl space is cool because it's underground. When the warm humid air contacts the cool surfaces, you get condensation all over everything- and mold is having a party. Critters love damp places, too. and mold doesn't help the health of the occupants or your home's resale value very much these days.

What's downstairs is upstairs. as the house sucks air from bottom to top it takes moisture, mold spores, odors, etc. upstairs to greet you. The humid air also raises your air conditioning costs in a significant way.

What's good about a vented crawl space? Nothing. 

Excerpt from Crawl Space Science.