What to Look For
If your toilet is leaking around the base or worse is staining the drywall of on the ceiling below, the problem is most likely a failure of the wax ring. This is a very common home repair. The following will guide you through removing the toilet and replacing the wax ring which is used as a seal. The first step is to turn off the water supply to the toilet, and then remove the two bolts that hold the toilet to the floor. It’s best to use either an adjustable wrench or box end wrench (usually 7/16”) to avoid rounding the edges of the toilet bolts, making them difficult to remove. If they are rusted or rounded off they can cut off with a hacksaw and replaced with new hold down bolts. Many of the wax rings have replacement bolts in the box. They can also be found in the same area the wax rings are displayed. Purchase the length you need for your installation. Also many have break-away sections to accommodate for varying floor heights.
The Details Make the Difference
As soon as you turn off the water supply, flush the toilet and hold open the flapper valve (inside the tank) until the water has drained out. Then dip as much of the remaining water out as possible, using old towels or cloths to finish the job. A common handyman trick here is to use a wet/dry vacuum. Without the vacuum you wont be able to remove all the water in the bowl, so be careful when lifting for the remaining water will leak out as the toilet is moved. Use caution here, toilets can be heavy and awkward to move around. I employ the use of a tarp to protect the floor and surrounding surfaces. If I can I like to finish the work right there in the bath when possible. There is an additional in depth set of instructions here.
Once the toilet is removed, scrape the old wax ring from the bottom with a 1” putty knife, removing as much of the old ring as possible. If you’re installing a new toilet, the only wax you’ll have to be concerned with is the part that remains on the floor flange. This can be removed with the putty knife and should be clean and smooth prior to applying the new ring.
There are several options on wax rings; my preference is the one with the attached flange. If you have changed the flooring, adding depth, then you should opt for one of the thicker flanges, but in any case, I wouldn’t go with the cheapest and thinnest.. Place the new ring on the floor, centering on the opening in the drain pipe, set the new anchor bolts (make certain they are turned properly to catch the toilet flange) and carefully set the toilet in place.
Once in place, apply firm even pressure, gently rocking to seat the wax ring. Then, place the washers on the bolts and tighten by hand, finger tight. Using a wrench tighten on one side a few turns and then the other to keep even pressure on the porcelain bowl. DO NOT OVER TIGHTEN OR YOU WILL CRACK THE PORCELAIN. Tighten only enough to stabilize the bowl and keep it from rocking.
Reconnect the water supply, turn on the water, flush, and check for leaks. If none are visible, caulk the contact point around the base of the toilet and the floor. This both stabilizes the seat and also leaves a clean smooth surface were dirt and germs cannot hide.