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  • Bernard Black

Crawlspace Basics

Updated: May 9, 2019

Crawlspaces are often neglected. After all, they are unpleasant, cramped and even a little dangerous. Understandably, most homeowners are reluctant to venture under their own homes to check on their home’s basic health. We wanted to share some of the basics of crawl spaces to help you keep your home safe from pest damage.

The Raccoon Mother

Last year, we were called to investigate a possible dead animal problem. Here is what we discovered:

A damaged vent caught the attention of a pregnant raccoon. She somehow fit through the vent, made a nest under the home (from debris, vapor barrier and insulation). Later she gave birth. She repeated this for at least three years in a row before the homeowner noticed the odd smell. At that point, about a fourth of the insulation was destroyed, the vapor barrier was fully contaminated and the smell of urine was overwhelming. This required nearly $3000 in repairs. It could have all been prevented by simply fixing a $25 vent!

Our Inspections:

Here are some things we look for during our evaluation of crawlspace issues:

Proper maintenance of the building vents. The screen on the vent should be ¼ inch or smaller (just small enough to prevent a pencil from entering fully). Vent screens are often damaged by utilities when they run gas pipes, cable lines through the vents, for example. Assure that the screen fits tight around pipes and cables.

The vents should be open except during freezing weather. This will assure that the crawl space can stay dry. Time open the vents!

There should be no exposed soil. All of the soil should be covered with 6mil or thicker plastic (vapor barrier quality). This will prevent moisture in the soil from getting into the home.

Check pipes, dryer vents and drains. There should be no drips or standing water. Dryer vents should only exhaust outside, otherwise moisture (and lent) will accumulate under the home.

The space should be free from rodents. A small amount of activity is normal, but high rat and mouse activity can lead to costly decontamination repairs!

Assure that there is no earth-to-wood contact. When soil is in direct contact with wood, the wood can become moist, leading to problems with fungi, termites and a host of other maladies.

Inspect for termites, wood beetle, carpenter ants and wood decay fungi. If any of these pests are found in the substructure, action is required to preserve the building.

Remove wood and other debris. Builders often leave wooden form boards or trash under buildings. Any wood in direct contact with the soil may initiate termite feeding and should be avoided.

Make sure that the crawl space hatch seals tightly. Raccoons, opossum and other animals can enter a crawl space via a broken vent or poorly sealed exterior door.

The crawl space should be accessible. This means that the soil must be at 18 inches at a minimum below the support timbers. Ideally, there is 24 inches or greater space for workers. The overall idea here is that a service person should be able to move around within the crawlspace without much trouble.

The smell of a dead animal, animal urine or feces, moldy smells and any other odd smells can indicate a problem. An ideal crawlspace should be dry and odor free.

If you are not comfortable maintaining your crawl space, we can help. Our crawl space clean-up program can include minor vent repair or full-scale decontamination and restoration of crawl spaces. Please contact us for further information.

Raccoon Joke:

Q: Why did the Raccoon cross the road?

A: To prove to the opossum that it could be done!

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