Here's how you can tell if your house has termite damage. First examine obvious areas of wood rot for termites. Some wood will look intact from the outside, but inside it may have been eaten away in a series of long tunnels. A sure sign of recent infestation is the presence of "frass", which is termite excrement. Pound on a post, beam, or siding, and if frass falls out like dust, be sure to call in an extermination specialist.