Eddie L

Drilling thru Concrete Block

I know there was discussion about this awhile back, but I thought I'd again put in my 2 cents.
Yesterday I had to make a 4" hole thru my 8" basement block, that was filled with concrete.
This was done for my exhaust fan.
I rented a Milwaukee hammer drill, 5/8" bit on a 12" shaft, and the hammer chisel all for $35.00 for the day....no hourly rate.
I proceeded by drilling about 10 pilot holes around the exterior of my sketched outline
Then taking the power chisel I just chiseled out the interior.
Luckily, I missed the rebar!
It took about 45 min.
With clean up, a little over an hour.
Hope this helps someone.
I know there was talk about using water to cool things down,, not using a hammer drill because of damage to the exterior of the block.
All I can say is, I've done this before and this way works slick as snot!
If I would have been thinking I would have taken pics, but the duct is already in place....sorry.
Ed

Frank Zimkas

I've had to do the same thing on different occasions. The hammer drill option will work, but for sheer speed and ease of use, a 4" coring bit is the only way to go. No water needed and available at most bigger rental yards. They'll cut right through rebar as well.