Wood in contact with soil, then is ideal for termite development. Natural wood serves as food and homesites. Occasionally, when a leaky roof or pipe provides moisture, termites can invade without solid contact with the soil. To check for termites, any wood near the foundation or soil should be probed with an ice pick or screw driver, especially the plates, header joists, ends of floor joists and any hardwood flooring. The tubes will resemble long streams of mud running up basement walls or along foundations.
Wider tubes indicate a more serious infestation.
Remember, infestations develop in soil. The termites enter the building through structural wood or foundation walls adjacent to the soil. In the case where houses are built partly or completely on slabs, infestation is through expansion joints, cracks and utility and sewer openings. If damage is found, there is no great hurry to apply control measures. Termites work slowly, and a few weeks delay is of little consequence.