How to Remove Humidity From a Crawl Space

Inspect the crawl space for signs of increased humidity such as mold or fungus formation, musty odors, "sweating" on metal pipes or duct work caused by condensation, or rotting wood. These signs will be more apparent in the spring and summer months; however, many, such as the rotting wood, will be present year round.

Begin with moisture management by routing drainage from gutters away from the house foundation. Grade the landscape near the foundation so that water will drain away from the house.

Check for cracks in the foundation and seal them with waterproof sealant made specifically for concrete. Purchase waterproof sealant for concrete at a local hardware store. Follow manufacturer's directions.

Look to see if access doors to the crawl space are below grade, which means that they are below ground level and therefore susceptible to water draining into them. Access doors should be at least four inches above the exterior level of the soil.

Ensure that all appliances in the crawl space vent to the outside of the building to prevent drainage or humidity from contributing moisture to the crawl space.

Install a dehumidifier, or if you already have air conditioning in your home, have the air conditioner duct vented into the crawl space to reduce the humidity. A return vent will also need to be installed to make the air conditioner work properly.

Install a sump pump or a drain with backflow valves to remove standing water from the crawl space if this is a factor in the excess humidity.