How would I go about attaching a toilet flange to marble tile over concrete substrate?
Not clear on what you are asking. Typically a toilet flange doesn’t attach to the tile, it attaches to the drain components and then is screwed into the substrate, generally through the tile. The flange can sit atop the finished floor and that is preferable but not necessary all of the time. There are also flange extenders and additional wax seals can sometimes be used to build up for the connection of the toilet to the flange/drain.
