Everything You Need to Know About Toilet Installation

If you start seeing cracks or leaks from your toilet, or it uses too much water when flushing, then you should consider replacing it. You may call in the plumber or go the DIY route. If you want to DIY, it’s not an easy task and may take the whole day, but it would save you some cost. In this case, here are the steps to follow.

Before installing the toilet

Before installing the toilet, examine the bathroom to ensure it doesn’t have manufacturing defects that may prevent its results in leaks or cause it not to seal thoroughly. Sometimes, the inlet connecting the bowl to the tank or the bottom outlet may be deformed and cause problems.

Be sure to confirm the toilet measurements and check the installation instructions before you cut the hole into the floor to install the waste line for the toilet.

Installing the toilet

  • Ensure the toilet foot is flat. Otherwise, it has a higher tendency to rock and break the seal, leading to leakage and odors.
  • Confirm that the floor frame for the toilet installation is adequate. Your toilet should ideally be between two sets of joists set about 12 inches on-center, and the blocking is nailed on one side of the drain as reinforcement for the closet flange area. This will reduce movement at the fixture that can break the wax ring’s seal.
  • Locate the flange assembly and toilet waste pipe in the finished and rough floor to space the toilet reasonably. If the toilet waste connection is too close to the toilet wall, it may make replacement impossible without moving the waste pipe which is a lot of work.
  • Cut the hole in the subfloor to fit the waste line and make it a little larger than the drain. Also, it’s ideal for the toilet to sit on the finished flooring, so you don’t have a dirt-trapping joint with the finished floor abutting the fixture. Make sure that the waste pipe connection opening has proper sizing. The waste hole should typically have a diameter between 3 and 4 inches. The waste pipe cutout opening must have a small diameter to securely bolt the toilet’s mounting flange to the waste pipe.
  • Secure the closet flange to the subfloor after installing it using stainless steel or brass screws. If you have a vinyl floor, the flange can be on the subfloor directly but if it’s a tile, raise the flange to the tile’s height using the plywood spacer. You can ensure longevity by using brass closet nuts, bolts, and washers instead of plated steel often packed with the toilet. Then place the sealing wax ring of the toilet on the closet flange before setting the bowl in place.

Be sure to get your toilet mounting bolts ready before you set the toilet on the toilet flange.

  • Install the two mounting bolts of the toilet by sliding the heads in the toilet mounting flange. Then position the mounting bolts of the toilet properly opposite each other and in a parallel line to the wall behind the location of the toilet. If you set the wax ring on the flange, it will help to hold the toilet mounting bolts and make them upright. Some people may prefer to securely push the wax ring to the clean toilet bottom around the waist opening of the toilet. Then you stand straddling the toilet’s bowl and hold it over the waste pipe. You may or may not need a spotter to lower the toilet base or bowl down from on top of the waste opening.
  • After setting the toilet and pushing it down to the toilet flange, rotate the toilet slightly right and left one or two inches to seal the wax rings together. You can also seal a single wax ring between the upper surface and the underside or bottom of the waste pipe and toilet mounting flange.

With this approach, you’ll be able to provide plenty of wax and a thorough seal that minimizes the risks of future leaks from the toilet base. In addition, the toilet bolts are supposed to protrude up through the mounting holes at the toilet base.

  • Tighten the nuts gradually on the bolt of the closet, alternating between the two sides until it’s snug but make sure you don’t over tighten it.
  • Lastly, apply a silicone caulk bead to the front and sides of the toilet foot and leave the back unsealed. This will enable you to spot leaks before it develops into severe damage.


Doing your toilet installation by yourself can be stressful and may take a whole day, but it’s not impossible. You may as well save yourself the stress by calling a professional plumber.

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