“How Can I Bore 2″ Holes in a Concrete Basement Floor?”

Question: Can I drill a two-inch hole through the concrete floor of my basement for the drain tube of an air conditioner? The nearest drainpipe is 25 feet away and I don’t want to install plastic pipes running along the floor. Will my plan cause problems?

Answer: I think your plan will work fine, and it’s a much better option than a pipe running across the floor. In fact, I’ve done he same thing as a way to get rid of condensed water from a high-efficiency propane furnace and it works well. The amount of water generated by an air conditioner isn’t large (less than a furnace), and it will easily seep away in the coarse soil underneath your floor. I’d try drilling a hole that’s considerably larger than the tube that leads from your air conditioner, with the pipe going down partway into the hole but not extending to the bottom.

A rotary hammer is the ideal power tool to use for this job. I use the one you see above all the time for drilling holes in limestone rock that I split with wedges and use for building. You can rent one at any rental outlet. A 2″ hole is about as small as you’d want to go, and when you get that big you’ll probably need to use what’s called a “coring bit”. This removes a cylindrical plug of concrete, as opposed to regular drills that just pulverize everything with the circle being drilled. You can rent or buy a coring bit from the rental outlet where you get a rotary hammer. These days you can find them in both corded and cordless options. Cordless will be fine for your job. Just be sure you get a “rotary hammer” and not just a hammer drill (not powerful enough for this job).