Dan Bowers @ Holmes Inspection Company
Although they’re small, termites can pose a big problem to homeowners. There are some practical ways, however, to reduce their infiltration into your home. You’ll be glad to know that none of these terminating measures involve Arnold Schwarzenegger and his battery of firearms.
Subterranean termites live in the soil. Their role in nature is to consume dead trees and debris, to help turn them back into the soil. Unfortunately, though, these termites can’t tell the difference between your home’s framing lumber and the dead tree in your backyard. In fact, some frustrated homeowners may even say that the termite likes the taste of a home better than the tree. But that point is arguable. Nevertheless, termites are hard to keep out of the house if there is an environment that will support them, such as high relative humidity.
Termite shields do not keep them out. They can crawl through seam laps. In fact, they only need 1/32 of an inch to get through. Termites can even get through minute cracks in a block wall and climb up the hollow blocks to the wood areas. Because builders throw debris in the back fill, there is often a lot of good eating.
Houses where the siding touches the grade (it should be at least 6" above the grade), slab houses, and below the grade window frames in window wells are vulnerable. Termites are found at or near ground level and seldom are they found above the first floor.
Termites must return to the soil regularly due to the moisture in the soil that they need. The oxygen in our air will cause the termites to weaken and die. There is less oxygen in the soil and they are better suited to the soil environment. This situation tends to restrict their movement too far from the soil.
The way to keep termites under control is to prevent them from getting to the structure or from reaching moisture. There are two basic types of control:
- Mechanical method: This method seeks to physically alter the building to prevent earth-to-wood contact. You should also control moisture around the home by changing the grade, installing downspout extensions, repairing leaks quickly, installing footing drains, and drying up a wet crawl space. These moisture-reducing procedures will also reduce the probability of termite entry.
- Chemical method: This method seeks to create a chemical barrier around the structure that the termites cannot penetrate. There are two types of chemical control: pre-construction and post-construction.
Pre-construction is the best and most effective because there is more access to the soil and a more complete chemical barrier can be set up. In addition, the soil under the slab can be pre-treated as well. For those buying new construction, be sure to ask the builder to treat the soil.
Post-construction is more difficult because you must work around the existing structure. It is not possible at all times to chemically treat some areas of the pre-existing building. The end result is often limited success. This means you need to rely heavily on changing the environment (i.e., reducing moisture, etc.).
Some chemicals that are used in soil poisoning are Heptachlor, Termidor, Aldrin and Dursban T.C. There are also numerous synthetic chemicals on the market. Chlordane was the chemical of choice for decades until it was banned in 1985, due to installation problems and an occasional poisoning from off-gassing. It was the most effective chemical used for this purpose because it would crystallize in the soil and remain stable for decades.