I believe there are various rubber "donut" bushings that can seal one pipe size inside the hub of another. Pick the closet flange you want to use and measure what it will be going into and sift through the seals on the shelf until you find the one that fits. Liquid soap is one way to ease the process of slipping those kinds of things together.Originally Posted by jod78
Some folks use Tapcon screws to fasten things to concrete, and others use lead inserts and stainless screws. The important thing here is that the toilet be held down firmly so the wax seal will not be compromised by tipping.