My BIL when he was alive had a WDI license in Texas and I helped him numerous times to treat for termites. If you have them and know that you have them, just applying a treatment around the foundation will not get rid of them. Probabilities are high that they are coming into the house via a plumbing penetration like a shower pan or at a tub or sink drain. You'll need to cut open the drywall and treat these areas as well. If you watch how much you cut the drywall and where, you can use a 8x16" screened vent to cover the hole. If the area needs to be retreated, the screen vent makes it real easy to access. The chemicals used by the pros are not available to you as an individual. He used a product called Dragnet Termiticide. For the areas inside the house he used a product called Timbor. Make sure whatever you use, if spraying inside, that the product is rated for interior use. A lot of these chemicals are real nasty so make sure to use full clothing while applying.
Subterranean Termites must return to the ground every 24 hours. That's where you treat creating a deadly barrier between the house and the ground. There are Formosan Termites that do not need to return to the ground and these require the house to be fumigated- not a fun thing. The Formosan are the worse termites to get rid of.
In Texas you must have a WDI license to buy the chemicals BIL used. I have found several of the professional termiticides at country feed stores available to ranchers. No license required and I've never been asked for proof of owning a ranch- just give me the money. Dragnet costs BIL about $140.00 a gallon which makes 100 gallons of chemical. That will treat an average size home of about 1800 sq ft single story, no basement. Research and Google are yer friend. Know before you start on a project like this as these chemicals can be dangerous.
