I wanted a toilet put in my basement. I just had a plumber come out to my house and cut the basement floor and install the pipes. They patched up the floor with new concrete mix. But when I look down through some small holes on the outer rim of the flange, I can see that the concrete was not filled in all around the "neck" pipe that the flange is connected to. If you think of the flange as a clock, then there is concrete filled in from about the 8:00 position to about the 4:00 position. But from 4:00 to 8:00 positions, there is a void area where I can see the white pipe neck down below the surface. Why wouldn't they fill in this area with concrete, too, so that the entire neck is encased in concrete? Did they do it wrong?