| Checking for mold and mildew under the tile as said above is a very good approach. You also want to check you toilet wax ring. I have had many situations where this the toilet was either improperly seated on the wax ring, or the wax ring has perished, thus removing the seal. These wax rings can be purchased for under $5. I recommend one that has a built in flange, this makes reassebly easy.
If you have had numorous backups, chances are a small portion of you wax ring has withered away.
This might sound nasty, but bend down and smell the base of the toilet, if its bad enough to knock you back, chances are the wax ring is your problem.
Other things to look for, is make sure you sanitary lines (drain lines) are properly vented. Having unobstructed vents for your drain system will keep them from "vapor locking" when a toilet is flushed, thus pulling the water out of your traps. |