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.

DDT.

Now available from your local World Health Organization office.