What The Heck? Holes In Basement Floor

Terrence

Hey guys.

Doing a job where there is a cement floor in the basement of a 1920's home. She wants tile down here, and there are holes drilled in the concrete floor around the perimeter. The holes are about 1-1.25", and are spaced apart about 3-4' within 6" of the walls. There is a second set of holes about 2' toward the middle exactly the same.

Can I tile over these holes?
What are the holes for?

Ive seen pest control done this way, but it was on the outside of the home... are these holes for that?

On a normal tile job, I would fill these holes in with mortar, but I am concerned about what they are for. If they need to not be filled I would certainly like to know.

I have never seen it like this, and would like to advise my HO wisely. Thanks in advance for any help.

gregj

Sounds like termite treatment. If so, the holes should have been filled. But there's nothing wrong with telling the HO that you don't know why they have holes in their basement floor and asking them if they want them filled.

Terrence

That makes me feel better, thanks!
Yes, many of them were plugged up with something (hard to tell what it is...), but much of that stuff came up with the mortar for the previous flooring.

SuperiorBuilt

I agree with Gregj. Back in the 70 and 80's exterminaters used to drill holes on the interior to treat for termites. If you had tile floors they would usually drill in the grout lines to save you the hassle of broken tiles if they were nice. Only problem was that found out the chemicals were also bad for humans too.
Wow now 20- 30 years later how technology has changed. Now exterminaters use baiting systems outside the house along the perimeter of the structure.

747

termite holes for a 100 percent fact. They drilled in my utility room floor around perimeter and also my den floor. Those are floors on cement. You should also notice exterior and interior holes in the block foundation. Once all that treatment is down then they install the outside baiting system.