Since termites must return to the soil at least once a day, the most effective method of attack is to poison the soil around the foundation of the house or building with special termite insecticides (e.g. chlordane, heptachlor, etc.)

Treating the soil around the foundation requires excavation and the handling of dangerous chemicals. It is best advised to contact a trained professional exterminator. To ensure complete protection, a 30 inch deep trench must be dug around the entire foundation. Part of the poison is poured into this trench, while the balance is mixed with the soil as it is replaced.

Many homes and buildings have concrete slab floors (porches, patios, and garage) laid on the ground right next to the foundation walls. Termites often come up through the soil under these slabs and work their way inside through cracks or open points where the slab meets the wall. The only way to poison the soil under these slabs is to chop holes through the concrete floor, then pour or pump the insecticide solution through.

Again, it is best to hire a trained professional exterminator for this kind of work.