Stubby wrote:
I have some crumbled spots in the concrete slab under my house. These
are at the edges where "tackless" strips used to be anchored. I'm
installing a floating floor now and want to patch the slab and prevent
insects from crawling in. Can anyone suggest a "permanent"
insecticide? In the old days we would have used chlordane but that has
been outlawed and is unavailable now.

Not sure what those two have in common but no, there is no permanent
pesticide.

Bob S.