Crawl space moisture control and drainage
Water gets under Goldsboro houses two ways: as humid air and as liquid water. Fixing a damp crawl space means dealing with both.
Moisture control is the part of crawl space work that keeps everything else from failing. It covers keeping rain and groundwater out, and pulling moisture out of the air once the crawl space is closed.
Keeping liquid water out
Start outside. Gutters that overflow, downspouts that drop water right at the foundation, and yards that slope toward the house send rain straight into the crawl space. Extending downspouts and regrading are often the least expensive fixes. When the ground itself is wet, as with soils that carry a seasonal high water table from December to April, an interior perimeter drain leading to a sump pump can move water out before it pools on the liner.
Pulling moisture out of the air
A closed crawl space needs one of the moisture-control methods in Section R409.5 of the North Carolina Residential Code. A dedicated crawl space dehumidifier is the most common choice. According to the Office of State Fire Marshal, the dehumidifier and exhaust fan methods don't require an H-3 heating license, while HVAC supply air and fully conditioned crawl spaces do. Crawl space dehumidifiers are compact, run on a humidistat and drain continuously, which a portable unit sitting on the floor can't reliably do.
Signs your moisture control isn't keeping up
- The musty smell in the house comes back in midsummer
- The dehumidifier runs nonstop but the humidity reading stays high
- Water collects on the liner after storms
- The sump pump runs constantly or not at all
- Condensation returns on ducts or pipes
Routine upkeep
- Clean or change the dehumidifier filter on the maker's schedule
- Make sure condensate and sump discharge lines run clear and away from the house
- Check humidity readings now and then, especially in July and August
- Keep the crawl space door shut tight and gutters clean
After a flood
Drains and dehumidifiers handle routine water, not a river crest. After flooding, have the crawl space checked before turning equipment back on.
What affects the price?
- How much water gets in and from where
- Dehumidifier capacity, electrical work and drain routing
- Length of interior drain and sump setup
- Outdoor grading and gutter work
Pricing comes from the crawl space company after someone has been under the house with a flashlight and a tape measure. We don't quote prices, and a figure offered over the phone before that visit is only a ballpark.
Where we connect you with help
Common questions
Does a crawl space dehumidifier need an HVAC license in NC?
Not for the dehumidifier method itself, according to the NC Office of State Fire Marshal. Supply-air and conditioned-space methods do require an H-3 heating license.
Do I need a sump pump?
Only if water actually collects in the crawl space. Many damp crawl spaces are fixed with gutters, grading and humidity control. An inspection will tell you which you have.
Related services
More background: Goldsboro crawl space guide.
Damp smell, sweating ducts or a floor that's started to dip?
Call and we'll put you in touch with a crawl space company that works in Wayne County.