I'm replacing a toilet in the basement where it slopes toward the drain. What is the best material to put under base of toilet so that it is level. Existing toilet has a filler of some type, but I'm not sure what it is. The back of the toilet is on the concrete floor and the front has a 7/8 in. gap. My wife has seen an episode on this specific problem, I would like to see it too. Does this website have an archive of past shows. Any advice is welcome.