Crawlspace Issues


Slab or crawlspace – which type of foundation do you have? One is not necessarily better than the other, and each have their pros and cons. Crawlspaces provide service access for plumbing, electrical, and heating and cooling systems, but they can have the perfect conditions to support termites. Let’s discuss some common crawlspace problems and how to fix them.

Excessive moisture

An abnormally damp crawlspace supports the growth of fungi and termites. Surface molds, like those found growing on the surface of floor joists, will not cause structural damage, but they do indicate a moisture problem that could support termites. Other types of mold, like brown and white rot, will eventually cause your wood to lose its structural integrity. Brown rot darkens wood and causes cracking against the grain, resulting in cube-like breakage. White rot makes wood spongy. A moisture meter can determine the moisture content of wood in your crawlspace. A moisture content of less than 20% prevents fungal growth and thwarts termite infestation.

If water is flowing into your crawlspace from the outside, it may be necessary to repair the foundation. Inside the crawlspace, a plastic vapor barrier should cover the majority (but not the entirety) of the dirt floor. Ensure that there are enough vents to achieve cross-ventilation and that the vents are not broken. Automatic vents that open and close with the changing of the temperature are preferred. If your crawlspace door is broken or non-existent, have it replaced with a sturdy door that seals and shuts securely.

Standing water

Standing water in a crawlspace is a serious issue. It could indicate a drainage problem or a plumbing leak. Water could be seeping in from outside the crawlspace. Make sure that gutter downspouts are directing water away from the foundation of your home. If your home is prone to flooding, consider sloping the crawlspace so that it drains to a sump. A sump pump can redirect the water back outside and reduce the moisture levels in your crawlspace.

Wood to ground contact

The crawlspace is not a sacred place, and many contractors will stuff it full of leftover building material and scrap. Be sure to remove any construction debris like wood and cardboard. Anything made of cellulose is potential termite food.

Refrain from using your crawlspace as storage.

Exclusion concerns

Broken vents, or vents without adequate screening, can allow insects, spiders, snakes, and rodents access to your crawlspace. Broken crawlspace doors can permit the entry of larger wildlife, like raccoons, opossums, and armadillos, which can lead to flea infestations of your yard and home. Check the perimeter of the crawlspace and seal up any holes or obvious gaps.

Other issues

Clothes dryer exhaust systems should vent outside your home and not into the crawlspace. That warm, moist air makes the crawlspace conducive to termite infestation. It will also attract critters trying to stay warm on a chilly night.

The paper backing on insulation can be eaten by termites. If insulation has fallen, be sure to rehang it properly. Any cellulose in contact with the ground can be easily found by foraging termites.

A note about crawlspace encapsulation

Encapsulation generally involves lining the crawlspace floor and side walls with plastic and sealing off foundation vents. Sometimes spray foam is used. Oftentimes, gaps are not left to allow for visual inspection of termites. Companies may not offer a termite warranty for a home they cannot fully inspect, because encapsulation greatly increases the likelihood that an infestation will be missed. Encapsulation may also void your termite warranty, so be sure to check with your termite control company before you commit to an encapsulation.