There was a recent thread in GQ about termite infestation, but rather than hijack that thread, I’ll seek opinions (expert and otherwise) here.
When my 5 year old house was built, a termite barrier of diatomaceous earth was put in around the foundation. Last fall I discovered termite tunnels in a couple of places in the garage. They originated from the joints in the concrete and migrated to the walls. Since the original barrier came with a 5 year warranty, the pest control company came out and spot treated the infestation in the garage. They drilled holes through the slab and pumped about 8 gallons of Tengard under the slab and down into the slab joints. Is this an acceptable treatment method, or merely a bandaid? Naturally I am a skeptic, but indeed I have not seen any sign of termites since then.
Their explanation for the infestation: typically during home construction, various contractors park their large ton work trucks on the garage slab as soon as the slab has set. But because the slab hasn’t had time to sufficiently settle on grade, added weight on the slab sometimes creates large voids underneath that termites are able to access. Is this a plausible explanation? 8 gallons seems like a lot, so there must have been some voids under there.
Third, now my warranty is running out, and the company is offering to renew the barrier and give me a 10 year warranty for $695. Because of the recent infestation, I don’t have much faith in this type of barrier now. It’s also difficult to keep various critters from digging around the foundation, so it seems the barrier could be easily defeated if disturbed. On the other hand, I‘ve had termites now. So I feel as though I should be more proactive in keeping them at bay. My last questions for the experts: should I go for the barrier, or is there a better treatment option I should look into? What about the quoted price/warranty? My house is 2800 sq. ft on a single level, so that is a lot of barrier to put in.