Replacing an old toilet

Scott Gibson, Contributing Editor

How difficult is it to replace an old toilet if you've never done this job before? And what kinds of problems are you likely to run into an old house?

I always approach plumbing warily, especially in an old house. Aging plumbing has a way of coming apart in inconvenient ways. Even when I start out with all the right tools and materials, lined up before me as neatly as a company of Marine recruits, something often goes awry.

That said, replacing a toilet is a job most of us should be able to handle.

Just be aware of a few potential trouble spots.

Look for signs of old leaks

There are three good reasons to take on this job.

  • First, when there is evidence of old leaks around the base of the toilet. Wood may be soft and spongy. Or the toilet may rock from side to side.
  • Second, if the toilet was manufactured before 1992 it probably uses too much water. After that, a government edict required a flush consume no more than 1.6 gallons of water -- half or less of the old standard.
  • Finally there may be a compelling cosmetic reason. Maybe your toilet is an ugly shade of pink, for instance.

Start by draining and removing the old toilet

In a nutshell, here are the steps you'll have to take, beginning with the removal of the existing toilet:

  • Shut off the stop valve, which supplies water to the tank, and flush the toilet. Use an empty yogurt container or something similar in size to scoop out the remaining water from the bowl and tank -- get as much as you can. Then use a rag or sponge to get the rest.
  • Disconnect the supply line from the tank, then loosen the tank bolts and remove the tank.
  • Back off the nuts that connect the base of the toilet to the toilet flange below.
  • Pull the toilet and walk it out to the garage (or the backyard if you intend to turn it into a planter).
  • Clean the toilet flange (the metal ring attached to the top of the waste line) by removing any wax left from the old gasket. You may want to stuff a rag in the waste line to keep sewer gases from getting into the house while you prep the new toilet.

Reverse the steps for the installation

To install the new toilet, you basically reverse those steps. Don't forget to remove the rag you stuffed in the top of the waste line.

Begin with a brand new wax ring to seal the base of your new toilet to the closet flange.

This seal is important. The first time I installed a toilet no one told me you needed one of these things. It took months to figure out the source of the pervasive odor downstairs.

Wax rings are cheap and reliable. A newer type of seal relies on rubber gaskets to make the seal but they can't be used with the lead waste lines still found in some old houses.

This is a good time to replace the stop valve if it looks corroded.

About the Author
An accomplished woodworker and carpenter, Scott Gibson is the former editor of Fine Woodworking magazine, and a former editor at Today's Homeowner and Fine Homebuilding magazines. He also is former managing editor of the Kennebec Journal, a daily newspaper in Maine.

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