Carpenter Ants & Your Crawl Space



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One of the issues with having too much moisture in your crawl space is that you are more likely to have pest infestations. Bugs need water to survive, so dripping pipes, standing water, and other sources of moisture, make your crawl space more attractive to them. Furthermore, once you have moisture, you’re more likely to have moist wood as even more incentive for certain pests, such as carpenter ants.

Intro to Carpenter Ants

Carpenter ants are black in color and the largest size of any ant, usually 1/4 - 1/2 inch in length. In the wild, they play an important role in the decomposition of dead trees and the creation of soil. Their main source of food in the wild is insects. Carpenter ants don’t actually eat the wood that they tunnel through. Carpenter ants live in colonies which are made of one wingless queen and wingless female workers. Once the parent colony has a couple thousand workers, it will then begin to produce winged males and females, who are capable of reproduction. After a brief mating process in the spring, the male dies and the female begins to looks for a nesting location. The ideal location is surrounded by decaying, wet wood such as a log or stump. The ants from this first nesting become the female workers of the new satellite colony.

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Nest Locations

Just because you see carpenter ants in your home doesn’t mean that there is a nest inside. It’s possible that the nest is located outdoors, and ants have entered your home in search of food. While insects are the primary food source in the wild, carpenters often search for food (especially greasy or sugary), inside homes. Foraging ants will normally come inside during the night, looking for both food and water.

Of course, it is also possible that there is a nest inside your home. If there is a parent colony outside, one of the satellite colonies may have created a nest inside, especially if there are areas of moist wood. Nests are often found in places such as porch pillars, wall studs, or the wall void behind a dishwasher. Be sure to check the areas around appliances, plumbing or other sources of water. Carpenter ants typically tunnel their way through wood to find hollow areas around it, but don’t actually make their nests in the wood.

Carpenter Ant Nest Locations

Source: Bruce Marlin

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Carpenter Ant Damage

Source: Nwbeeson

Damage from Carpenter Ants

Once inside, carpenter ants can cause damage to wood and other soft materials throughout your home. Carpenter ants will excavate tunnels through wood in search of nesting locations. While they will tunnel through any type of wood, carpenters prefer moist wood with fungus. In addition carpenter ants may tunnel through building materials such as insulation.

Depending on the extent of the infestation, the damage can range from minimal to severe. Generally, carpenter ants do not cause as much damage as termites. However, if there multiple colonies within your home, carpenter ants are capable of causing structural damage. This is especially true if multiple colonies go undetected for a large amount of time, making it crucial to check regularly for signs of damage.

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Carpenter Ants vs Termites

Source: Adam B. Lazarus

Carpenter Ants vs. Termites

Carpenter ants and subterranean termites are often confused since they both tunnel through wood and at first glance, look similar. Ants and termites actually have some distinct differences if you look closely.

Most notably, worker carpenter ants are dark black in color while worker termites are white. Worker carpenter ants can be as large as 1/2 inch in length while the typical worker termite is only 1/4 inch in length. Both reproductive ants and termites are dark in color, however, there is still a size difference. The carpenter ants can be as big as 3/4 inch while the termites range from 3/8 inch to 1/2 inch.

Another difference can be found in the antennae. Both reproductive carpenter ants and worker carpenter ants have a bend in their antennae. Conversely, subterranean termites have straight antennae divided into segments. In addition, carpenter ants have a noticeable waist while termites have a straight body. You can also find differences in the way that the pests tunnel through wood. When a termite is hollowing out wood, it leaves behind a mud like substance. This is not the case for carpenter ants. Instead, you will find shredded wood, similar to sawdust left behind by ants.

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Prevention of Carpenter Ants

To help prevent carpenter ants from invading your home, be sure to remove any stumps, logs, or other excess wood located within 100 yards. It is also helpful to trim back any tree branches or vegetation that may be touching your home. This will help prevent colonies from forming within the vicinity of your home. As for inside your home, keep an eye out for damage to the structure, such as holes or gaps, and fix them promptly. This is especially true, if you discover any rotting wood. Furthermore, pay attention to plumbing in your home for potential leaks and moisture problems.

Another important area to maintain, that is often overlooked, is the crawl space. Regularly inspect your crawl space for damage and signs of excess moisture. Check to make sure that all cracks and gaps in the foundation walls are sealed. To further prevent pests, it’s a good idea to encapsulate the crawl space and use a dehumidifier to maintain the moisture levels.

If you do discover signs of carpenter ants, it’s usually best to call a pest control professional. It can be difficult to track all of the various satellite colonies and determine the source of the initial infestation.

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"Carpenter Ants (Department of Entomology)." Department of Entomology (Penn State University). Penn State University, Jan. 2014. Web. 13 Sept. 2016.
"Carpenter Ants." Entomology. University of Kentucky Entomology, Nov. 1997. Web. 13 Sept. 2016.
Morgan, Peggy. "Carpenter Ants." Methods in Integrated Pest Management. State of Washington, Aug. 1997. Web. 8 Sept. 2016.