Crawl space moisture control
Most crawl space damage starts with water, either as humid air or as rain running the wrong way. Here's how each is handled.
There are two ways moisture gets under a Lowndes County house. One is humid air, which in summer can carry more water than the cooler air under the floor can hold, so it condenses on ducts, pipes and wood. The other is liquid water: rain off the roof, runoff from a neighbor's yard, or groundwater on a low lot. Good moisture control deals with whichever one you have, and often both.
Fixing the outside first
- Gutters and downspouts. Clean gutters and extensions that carry roof water well away from the foundation.
- Grading. Soil that slopes away from the house, not toward the vents and access door.
- Sprinklers and beds. Irrigation aimed away from the foundation, and mulch beds that don't trap water against the wall.
Handling water inside the crawl space
- Perimeter or interior drains that collect water along the foundation
- A sump pump to carry collected water out, ideally with a discharge that doesn't run straight back
- Drainage matting under the liner where the floor stays damp
Drying the air
In a sealed crawl space, a dehumidifier built for crawl spaces, or a small supply of conditioned air from the home's HVAC system, keeps humidity down. DOE's Building America research found humidity reductions of more than 20 percent in unvented, conditioned crawl spaces. A household dehumidifier from a big-box store usually isn't meant to run in a dirt-floored space for years, so ask what model the company recommends, how it drains and who services it.
After a big storm
Once heavy rain has passed, look through the access door for standing water, a floating or displaced liner, or wet insulation. Turn off power to any equipment sitting in water and call before crawling in.
Pricing comes from the crawl space company, after someone has been under the house and measured it. We don't quote prices, and a number offered before anyone has looked at the space is only a guess.
Where we connect you with help
Common questions
What humidity should a crawl space be kept at?
Ask the company what target they set for your space and how they'll monitor it. Many install a humidity readout you can check without crawling under the house.
Do I need a sump pump?
Only if water actually collects in the crawl space. Many damp crawl spaces have a humidity problem, not a groundwater problem, and fixing gutters and grading may be enough.
Related services
More background: Lowndes County crawl space guide.
Musty smell, droopy insulation or a floor that gives underfoot?
Call and a crawl space company that works in Lowndes County will take a look under the house.