I'm doing a half-bath remodel, and am preparing the concrete subfloor for tiling. The closet flange on the old toilet was not actually screwed into any concrete and had just been glued into place. As you can see in the pictures, there is about a 1/2" x 2 1/2" gap around the sewer line, where I believe the closet flange would ordinarily be anchored into concrete subfloor.I was planning on using structural concrete repair, like this one, to fill in the space around the sewer line so that I would have something to actually drill into and secure the new closet flange instead of just gluing it to the sewer line. I wanted to get a second opinion on here first on whether this is the correct way to go, or if that prior gap and lack of anchoring screws has some purpose (i.e., maybe there isn't supposed to be concrete touching the top of sewer line?). Thanks for your help! via /r/DIY http://bit.ly/2FAeTGz
