Crawl space moisture control in Dothan
A crawl space can be wet from rainwater, from soil moisture and from humid air, often all three. Here's how each is handled.
Moisture control under a Wiregrass house starts with finding where the water comes from. The order matters: stop liquid water first, cover the ground second, and control the air last.
Step one: rainwater
- Gutters and downspouts. Roof water dumped at the foundation is the most common cause of a wet crawl space. Extensions or buried lines carry it away.
- Grading. The ground should fall away from the house. Settled backfill and raised flowerbeds often do the opposite.
- Interior drains. Where water still gets in, a perforated drain inside the foundation can carry it to a sump basin, and a pump sends it outside.
Step two: the ground
A sealed ground liner keeps soil moisture out of the air. Around Dothan, soils with dense, slowly permeable lower layers can hold water near the surface after heavy rain, so a good ground cover matters.
Step three: the air
In a closed crawl space, a dedicated dehumidifier on a humidistat is the usual tool. The 2021 International Residential Code, which Dothan enforces, lists dehumidification sized to remove 70 pints a day per 1,000 square feet as one way to meet its unvented crawl space requirements, along with continuous exhaust and conditioned supply air. Crawl space units are compact and drain continuously, which a portable unit sitting on the liner can't do reliably.
Questions to ask about a sump
- Where does the discharge go, and will it end up back at the foundation?
- Is the basin lidded and sealed under the liner?
- Is there an alarm, and what's the plan for power outages during storms?
Signs the system needs attention
- The musty smell returns in midsummer
- The dehumidifier runs constantly without lowering humidity
- Water on the liner near the unit, walls or sump
- A pump that never shuts off, or never turns on
The crawl space company sets the price after it has inspected and measured the space under your house. We don't quote prices, and any figure you hear before someone has looked underneath is a rough guess.
Where we connect you with help
Common questions
Should I open the crawl space vents in summer?
In southeast Alabama, opening vents in summer usually lets in more moisture. DOE research notes that outdoor air in humid climates is often wetter than crawl space air.
How often should a crawl space dehumidifier be serviced?
Follow the manufacturer's schedule for the filter, and check the drain line and humidity reading a few times a year, especially in summer.
Related services
More background: Dothan crawl space guide.
Musty air, wet insulation or a floor that's lost its footing?
Call and get connected with a crawl space company that works in Dothan and the Wiregrass.