A toilet waste pipe in my rental unit sits about an inch higher than the floor surrounding it. This is my wife's old house. About 10 years ago my wife had somebody build a "pedestal" for the toilet out of 3/4" plywood to make up the difference. The toilet keeps coming loose now. I replaced the bolts and wax ring about 1 year ago and it's loose already.
Is there any better way to deal with this besides replacing the old metal waste line or the entire floor/sub floor,which are both still in good shape?