I posted this in the pool forum, but this may be more of a masonry question.

I am about to replace the single main drain in my concrete pool built in 1965. I will be installing two new drains. I'm looking for advice on the size of the cuts in the concrete to allow sufficient space for the new concrete. The drains are approximately 8" in diameter and I will be using 1.5" pipe. I want to make sure that the new concrete is structurally sound when the job is complete. I have read that hydraulic cement should be used when filling in the openings. Does this sound prudent? Any comments/advice would be appreciated.

 

IXNAY on hydraulic,,, don't know where you read that drivel,,, how wide will the drain channel be ? realize you'll likely encounter rebar

 

The drains will be about 8” in diameter and the pipe will be 1.5”. I am trying to cut as little as possible but want to assure a solid patch. Maybe a 6-8” channel for the pipe and 12” squares for the drains?