After setting the tank on the toilet, tighten the bolts, alternating from side to side, until the tank is secure.

One of the most popular ways to add value and comfort to homes today is to remodel the bathroom, which usually means you will install a toilet. Part of that project will almost certainly require removing an old toilet and replacing it with a new one, which can be a messy and frustrating task. Follow these tips on how to install a toilet for an easier job and a better outcome.

Remove the old toilet

First, turn off the water supply to the tank at the wall shutoff valve. Don’t remove the feed pipe yet or water from the tank will soak the floor. Flush the toilet, holding the lever down until as much water as possible has drained out. Then lift the top of the tank and use a sponge to remove any remaining water. Use a sponge and cup to remove any water remaining in the bowl.

Unscrew the supply pipe from the shutoff, putting a small towel beneath it to catch any water. Since you will discard this pipe, you can use channel-lock pliers. Pry off the bolt caps on the toilet base to expose the nuts on the mounting bolts. If they are rusted and difficult to remove, use a hack saw or a cutoff wheel.

When you remove the toilet, the gasket will be dirty so protect the floor by covering it with plastic or a dropcloth. If the toilet is stuck to the floor with caulk, rock it gently to break the seal. Carefully lift the toilet and tank, and set it on the plastic or carry it out of the building.

Plug the exposed drain hole to keep gases from escaping into the room. Be sure to use a rag or other material that cannot fall into the drain line. Use a putty knife to remove any of the old wax seal that remains on the mounting flange. Also, clean up any caulk that remains on the floor.

Set the new toilet

Before installing a toilet, thoroughly clean the area and be sure the mounting surface is level.

If the tank is not attached to the bowl yet, setting the toilet will be easier. Turn the bowl upside down (put padding on the flooring to protect the flooring and toilet bowl edge) and press the wax ring in place with the plastic sleeve pointing away from the toilet. The sleeve goes into the mounting flange and waste pipe.

Insert mounting bolts into the mounting flange and use putty to keep them standing and correctly aligned. Remove the plug from the drain hole and carefully lower the bowl on to the bolts. Push down on the toilet bowl firmly and evenly to compress the wax ring. Never rock the toilet to compress the wax ring as it can result in uneven compression and leaks.

Put plastic retaining washers on the bolts, followed by flat washers. Hand-tighten the nuts. Then using a socket, tighten the nuts twice on one side and then twice on the other. Continue until the nuts are secure, but don’t over tighten or you risk breaking the toilet base. As you secure the toilet, continue to check that it is level.

The toilet should rest snuggly to the floor. If it doesn’t, shim the base with off-cut lead flashing from a roofing supply house. Slacken the nuts slightly and push in the shim material until the toilet bowl sits securely. Break off the bolt tops if they stand too tall; it may be necessary to cut them using a hacksaw or cutoff wheel. Snap decorative caps onto the bolts.

Install a toilet tank

installing toilets

With the tank installed, connect the new feed pipe to the shutoff valve.

Place the rubber gasket between the tank and bowl, put the rubber washers under the mounting bolt heads, and set the tank on the toilet. Tighten the bolts, alternating from side to side until the tank is secure. Use a level to ensure the toilet is level.

With the tank installed, connect the new feed pipe to the shutoff valve. Use the correct wrench size to avoid marring the new fittings. Open the valve and check for leaks. Flush and check again for leaks and proper operation. Caulk the base of the toilet at the floor with silicone caulk. Install the toilet seat.

—By Steve Sturgess

Tools and materials you’ll need

  • Adjustable wrench or set of wrenches
  • Level
  • Hack saw
  • Putty knife
  • Wax bowl ring
  • Toilet hold-down bolts
  • Plastic bolt caps
  • Kitchen & Bath silicone caulk and gun
  • Plastic or dropcloth
  • Padding to protect new toilet
  • Sponges and rags

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