Yes, you would still apply Termidor SC or whatever termiticide you are using in the 6 in x 6 in trench at the standard rate of 4 gallons per 10 linear feet. Where you would apply additional product would be where there are footers, where you would use a termite rod or hollow tube to apply additional product from grade to the top of the footing. Per page 7 of the product label:
When the footing is more than 4 feet below grade, the applicator has the option to either (1) trench and rod to a minimum depth of 4 feet into the trench along the foundation walls or (2) trench alone along the foundation walls to a minimum depth of 4 feet. The actual depth of treatment will vary depending on soil type, degree of compaction, and location of termite activity. When the top of the footing is exposed, the applicator must treat the soil adjacent to the footing to a depth of 4 feet but not to exceed the bottom of the footing. DO NOT treat a structure below the bottom of the footing.
Drywood termites are all contained in a piece of wood. They do not go back to the ground like subterranean termites. So if you did a trench with Termidor it will not treat the Dry wood termites. Please see our Drywood Termite Control Page.
If you are able to access the soil around the pipes, yes, it would be recommended to treat the top few inches with Termidor SC around them. There is no harmful fumes released.
Sometimes the ground is slow to soak up the Termidor SC you place in the holes. You may need to fill the holes, then go work on something else for an hour, come back and fill them again, go work on something else.....3 to 4 times to get the proper amount down the holes.
Rodding under the slab of a house from the exterior is a complex and detailed process that we do not recommend attempting yourself. We recommend that you contact a local reputable termite company for an inspection and estimate for something like this. If you have termites in the home, then you can spot treat where there are active termites using a ready-to-use termiticide foam such as Termidor Foam which will transfer throughout the rest of that termite colony.
There are 4 bottles to a case of Termidor SC. For this particular product there is not a lot discount available but we do offer fast, free shipping! We apologize for any inconvenience. Termidor SC is labeled to treat carton nests only away from the structure. The trench and drilling up against the foundation of the structure is very important. Please refer to our termite treatment article for additional helpful information on mixing and application.
Termidor SC can be applied to the soil topically (1 ft up and 1 ft out directly up against the foundation) and in a trench for termite control. There should not be any harm done to any grass sprayed.
Termidor SC can be sprayed twice a year at the rate of 0.8 oz per gallon of water and up to 4 times a year at the rate of 0.4 oz per gallon of water.
If that expansion joint is the only area of activity and Termidor SC was used for the initial treatment, most professionals would just treat that area of localized activity. It is possible the termites there came from a colony deep under the soil surface where they would not have come into contact with the existing liquid barrier. You would treat the expansion joint similarly to how you would treat the foundation, using 4 gallons of solution per 10 linear feet, applying evenly into drilled holes. Instead of placing the holes all on one side, however, you would drill them in a zig-zag pattern along the expansion joint. Please let us know if you have further questions.
Termidor SC if sprayed around structure perimeters for ants and other insects can be reapplied every 6 months. If applied in a trench for Termites, it will bind with the soil and last up to 10 years.