I recently took on a job for a buddy that has a 3inch ID waste pipe which is concealed in a concrete floor (for a toilet). This pipe seems to be cpvc? def. not pvc its got a sandy tint to it. I have been looking for toilet flanges that are for this application and cannot find anything. I dont know what was on the old toilet, im sure it got pitched with the old toilet. If you have any suggestions it would def. help me out.