Many insects and pests reside in firewood, including termites, woodborers, carpenter ants, horntail wasps, bark beetles, centipedes, cockroaches, spiders and sowbugs. These pests often crawl out of their tunnels a few days after the wood is placed in a warm place, such as a garage. Heat also may activate insect eggs laid in firewood, causing insects to crawl out of the wood into your home once they have hatched.
The insects in firewood aren't likely to cause structural damage. For example, carpenter ants or beetles found in firewood usually won't bore or eat into the wood in your home, even if you store firewood in your garage or bring firewood inside. Many people find insects in their home frightening or annoying, but if you aren't bothered by bugs, you may keep firewood in your garage as long as the wood stays dry.
Keeping firewood in a sunny, exposed location helps avoid insect or rot problems. Firewood often begins to decay if it touches the soil or is stored in the shade, so place it in a sunny location on a rack or other structure at least 18 inches off the ground. Stack wood loosely to encourage drying, and cover it with a tarp to keep rain and snow off. Keeping firewood at least 25 feet from your home reduces the chances that termites or other pests will move from the firewood into your home.
If flying insects crawl out of firewood when you bring it into the house, you may spray them with an aerosol spray that contains pyrethrins or other insecticides. Don't treat firewood with insecticides; you may kill some insects, but the chemicals can cause toxic fumes when you burn the wood. If you want to keep a few pieces of firewood in your home for decoration, heat them in the oven at 150 degrees Fahrenheit for 20 minutes to kill pests, eggs and fungi.