Treating Termites Inside the Wood Itself

What Direct Wood Treatment and Foam Injection Is and When It Is the Right Call

Subterranean termites feed inside wood and leave the surface intact, so the first job is finding the active galleries. The technician probes suspect wood with a sharp tool, taps for hollow spots, follows mud tubes to where they enter the framing and checks for live workers. Sill plates, band boards, joists near piers and door frames that touch a slab are the usual places here, because they sit closest to damp soil.

Once a gallery is located, it is opened with a small drilled hole or through an existing exit point. A liquid termiticide is injected where the wood is solid enough to hold it. Where the wood is hollowed out or sits against a void, a foaming termiticide is used instead. The foam expands to fill the gallery and the space behind it, then settles into a thin film that coats the inside surfaces. Termites moving through the treated wood pick it up and carry it back through the gallery.

This is the right call when the inspection finds live activity in wood we can reach, when a slab or porch puts framing in contact with soil, or when a single door frame or window sill is the only active spot found. It is not a whole house treatment on its own. Termites in the wood came from a colony in the soil, and the soil still needs to be treated, whether by trenching and applying a liquid termiticide or with termite bait stations around the perimeter. Direct treatment handles the termites already inside. The soil work handles the ones that would follow.

What to expect: small drilled holes that are plugged when the work is done. Foam may push back out of a crack for a few minutes and is wiped away. Wood that has been hollowed out is not restored by treatment. If the inspection finds a joist or sill plate that has lost its strength, that piece gets sistered or replaced as a separate repair, and we tell you before that work begins. After treatment we return once a year to inspect for new activity.