We have a toilet in the basement that was leaking nastiness all over. Hubby had fixed it twice, but it never stayed fixed. He was frustrated, and understandably so.
The problem was that the back-flush toilet (used because of the cement slab underneath) combined with the rigidity of the sewer pipe and wax gasket meant that the gasket was constantly becoming unseated. And leaking.
We discussed options. Drill out and plumb the cement slab. Ugh. Make a new, super-duper-solid platform for the toilet. Possible but still ugh. And no guarantee of working.
I looked on Google for a gasket that has a little give in it. I found and ordered the "Sani-Seal" gasket. For good measure, we decided to add a flexible rubber coupling onto the pipe itself, to make it slightly less rigid.
Today, we installed everything. We're crossing our fingers that there will be no more leaks!