Inside the crawl space you would need to trench around any piers that hold up the home but the outside trench would be all that is required for the actual foundation if you are using Termidor. The Termidor will last for 10 years to protect your home. Please take a moment to look thru our pest control guide for termite treatment.
Termidor SC is said to last longer simply do to research. Termidor has been on the market longer and has proven to last 10 years. Taurus has not been on the market long enough to prove that.
While you can use Termidor SC to treat voids in your subfloor, we would recommend to use Boracare instead because it can be applied to raw wood, be absorbed and last the lifetime of the wood. You can use Termidor SC in your crawl space if there's soil, you can trench around the piers to protect your home.
Termidor SC is not labeled to be used inside except for spot treating active infestations. If applied as a crack and crevice spray inside cabinets it would be recommended to thoroughly clean the area with warm soap and water or an all-purpose surface cleaner.
Termidor SC is a very safe product and widely used by professional companies inside homes every day across the country. Termidor SC is odorless and does not have any fumes. You only need to wear a face mask if you will be doing the application in a poorly ventilated or enclosed area. All other applications will require you to wear long sleeves, long pants, shoes and socks and gloves. Be sure to wash your hands after the application before you eat, drink, chew gum or use the restroom.
The answer to this question is also in our How To Do A Termite Treatment Article. You will want to use the Termidor product. For your concrete areas against the home, you will need to get the termiticide underneath the concrete against the foundation. To do this you will need a hammer drill with a 1/2" x 18" drill bit. You drill holes throughout the concrete about 3-4 inches away from the wall or foundation, and about every 10"-12" apart. Once the holes are drilled, you fill at the same rate you did the trench, 4 gallons per 10 feet. To fill these I would recommend using the one gallon sprayer on a "pin stream" setting so you can force the liquid down the hole and not splash it everywhere. You can also use a funnel and pour the termiticide down the holes. It is difficult to get 4 gallons per 10 feet in the holes, so it is important that you use a long drill bit, at least 18" long so you can bore out enough dirt to hold the termiticide. Once the holes are filled all you need to do is patch them with a concrete patch filler you can buy at Home Depot or you can use our Trebor plugs that will close the hole with no concrete mess.
As for your areas with rock over dirt, again - you need to get the termiticide product down into the soil to be most effective. We recommend digging a 6in x 6in trench to pour the solution into the ground.