Termites spread by swarming, and they can enter your attic through vents. Since attic wood is usually unpainted, anywhere they land they can start chewing. A borate treatment prevents this by making the wood inedible to termites. The borates work by killing the protozoa in a termite’s stomach, leaving them unable to digest wood. Because borates are derived from boron, a natural mineral, and attics typically remain dry, the protection can last indefinitely.