Jonathan writes: I have been finding little piles of wood shavings on my backyard deck, along the bottom of the exterior wall of the house (see photo). Does this look like a sign of termites or carpenter ants?
Steve Bliss, of BuildingAdvisor.com, responds: Wood shavings like these are most likely the work of carpenter ants. Carpenter ants excavate wood for nesting, but do not eat wood like termites do. Like termites, carpenter ants are attracted to wood that is wet and softened by wood decay. Termite droppings (frass), however, tend to be very small pellets, ranging from light brown to black in color. Piles of very fine sawdust might be evidence of powderpost beetles.
To control carpenter ants, the first step is to solve the water leakage problem. This will prevent further rot and discourage the carpenter ants from taking up residence. If the damage to the framing is extensive, you may need to open up the wall and repair the section that is damaged.
If your home lies in a wooded area, it is difficult to keep carpenter ants out of your house altogether. Even if they are not living in the walls, these large black ants may visit the house regularly to forage for food.
A very effective and non-toxic treatment for carpenter ants is boric acid, which you can buy at any hardware store. Sprinkle it liberally along the paths favored by the ants – behind and under kitchen appliances, for example.
If you are building in a wooded area, it’s a good idea to sprinkle boric acid along the bottom plate of your wall framing and other hidden cavities before they are enclosed. The boric acid will continue working for many years.
Boric acid, also called borax, is the same material used in the old washing formula “20 Mule Team Borax”. It is harmless to humans and pets, but toxic to carpenter ants and termites. Wood treated with borates provides a non-toxic alternative to pressure-treated wood, but it cannot be used in exterior applications because the borates will gradually leach out of the wood when exposed to rain.
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