How to Get Rid of Moisture in a Crawl Space

Crawl spaces under homes can be welcomed additional space to store the extra items that will not have room in the garage or shed. For those that have concrete surface spaces, consider yourselves fortunate. These finished crawl spaces have sealed protection against unwanted water and create much appreciated surface area to stow away several items as storage.

Those that have primitive crawl spaces with dirt or gravel floors do not enjoy the same storage and water protection benefit. These raw conditions often render the added space unusable when it comes to storage and can create a welcomed environment for nuisances as pests and water seepage. Seepage and high humidity in a crawl space are fairly common occurrences that unfortunately have the effect of creating a musty smell in the home. The good news is there are effective and inexpensive ways to remove the musty smell in the crawl space and make it moisture free.

Detect Source of Problem

The mildew scent coming from crawl space indicates there is some degree of moisture finding its way in whether through the floor or foundation walls. Examine the ground and check for dampness. Also look at the foundation walls for any signs of cracks or holes where water could potentially trickle in. If cracks in the wall exist, such gaps will need to be sealed to avoid further moisture problems. Severely damp ground in the crawl space can often be the result of poor drainage from roof after a rainstorm. Inspect and insure downspouts are effectively carrying water away from the home. Also inspect hard surface areas adjoining the home such as walkway and patios to confirm these areas are not sloped towards the home. These pitched surfaces can also contribute to excess seepage in the crawlspace during periods of heavy rainfall. These surfaces will most likely need to be lifted or "mud-jacked" to tilt slab away from home or replaced entirely to avoid reoccurring seepage problems with your crawl space.

Inspecting Wood surfaces of Crawl Space

Examine all wood surfaces in the crawl space for any kind of mold or mildew presence. Clean the wood and replace wherever possible. If the wood has suffered serious moisture damage, it would be wise to bring in a carpenter to assess and repair overhead joists. Due to the serious structural integrity of these fixtures, this repair is best to be left to the professionals.

Removing Mildew Smell in Crawl Space

There are several ways to get rid of musty odor in crawl space. The first objective to conquering the smell is to makes sure there is ventilation in the crawl space. A small vent is usually located in the crawl space wall and should be clear of debris. If for any reason the space does not have a vent in the wall, consider having one installed. Ventilation of this space if very important to keep allows fresh air in and the dead air to escape. Also be sure the vent is screened to keep out unwanted pests.

Consider using a dehumidifier in the crawl space to accelerate drying out the crawl space and removing some of the odor. The dehumidifier will be very important during the warmer months of the season and should be considered to be used year around in more temperate climates. A good quality dehumidifier will include a long drain tube that can be routed to a floor drain in the basement. This feature allows the homeowner to avoid having to manually empty the dehumidifier bucket daily.

Finally add some additional odor absorbers to the raw ground area. If the space is completely dirt or pea gravel, consider application of lava rocks. Lava rocks are porous and have the ability to absorb some of the moisture and associated odor from the ground. Also consider applying a few air fresheners throughout the space. Many of these air freshener devices can be attached through adhesive stickers that will fasten to the joists in the ceiling.

Vapor Protecting the Crawl Space

The final step to eliminate the musty smell from crawl space would be installing a vapor barrier. This can be accomplished one of two ways. One way is very expensive and the other is not. The expensive route is to have concrete slab poured over the raw space creating a permanent flat surface that will serve as a bonus storage area for years to come. This is probably the most recommended way to alleviate the problem if money is no issue.

The inexpensive way to create a vapor barrier in the crawl space is by installing a thick sheet (5 to 6 mil) of polyethylene. Cover the entire floor as well as run the plastic up the walls. Be sure to overlap the plastic as it is laid down on the floor weighing the sheets down with heavy objects such as bricks or large stones. The plastic applied along the crawl space concrete walls can be fastened with heavy duty tape or with treated wood cuts and masonry nails.