# Punching a hole in concrete

• posted on November 22, 2005, 12:36 am
I need to put a hole in a basement floor. To save my wife all the dust, I am going to drill holes with a hammer drill, then break out the concrete. The hole will be about 30 inches square. Question: How many holes would you drill around the perimeter? Size of drilled hole? I have a 3/4 in hammer drill.. How deep do I need to drill the holes. I was thinking of going right through the slab. Thank you for your time.
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• posted on November 22, 2005, 2:55 am

better, I would go all the way threw . The best way would be hire a concrete cutting Co.don't know about the cost but they will take that stepping stone with them.
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• posted on November 22, 2005, 3:24 am

Well, do the math. 120 inches divided by .75 if you use a .75" bit. Looks like 160 holes. 240 if you are going to use a .5" bit. That is a LOT of drilling. Going deep enough to get through the slab is also a LOT of drilling. And, you WILL be hitting aggregate, rebar and/or wire.
It can be done with a drill, but why would you want to do it that way?
You could also do it with a hammer and chisel, but that would take you two forevers.
Do it once, do it right. Rent a concrete saw, wet the concrete, and tell the wife to cope. Or hire a concrete sawing company.
Steve
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• posted on November 22, 2005, 3:28 am

Most basement floors are 4 inches thick. Easy to break out with a sledge hammer. Once you have the start of the hole, you can control the break by undermining.
It won't give you a perfect 30 x 30 square but it will make little dust and is easy to repair once you have done whatever it is you are going to do.
Speaking of which, why are you doing this? Adding a footing? A sump pump? Burial ground for dead cats?
Ken