How to Install a Toilet

man plumber in uniform installing toilet bowl using instrument kit professional repair service

Written by My Home Handyman

April 26, 2022

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It doesn’t matter if you’ve just purchased a home or are looking to make changes to your current one. There are times when you simply need to change out the toilet and get a new one. But after you have purchased the new toilet, how do you get it installed?

Thankfully, there is a consistent method for installing a toilet. You have to prep the floor for installing the soil pipe and closet flange. After soldering the stop valve:

  • Install the wax ring and set the bowl into place.
  • From there, install the tank and then set up the seat assembly and supply line.
  • Put the finishing touches and ensure that everything is working as it should before calling it a day.

Step 1: Prepare the Soil Pipe and Floor

The soil pipe is what carries the waste out of the toilet and away from your home. Start by stuffing a rag into the soil pipe in order to prevent hardware from falling into it and gas from the sewer from coming in. Make sure that the hole in your floor is large enough to accommodate the flange all the way up to the collar.

You can cut away excess flooring to accommodate, but don’t cut the joists. Make sure that you dry-fit the soil pipe to the closet bend, placing the flange to fit over the soil pipe. Measure the gap between the flange collar and the finished floor. Finally, remove the soil pipe and trim it to the measurement, removing burrs. Dry-fit the flange to the soil pipe and the pipe to the closet bend so that the collar of the flange rests on the floor.

Step 2: Installing the Closet Flange and Soil Pipe

Wipe PVC primer on the outside of one end of the soil pipe and the inside of the closet bend, twisting the pipe into the bend. Twist the flange and press it onto the soil pipe until the collar of the flange sits on the floor.

Rotate that collar until it is sitting to the left and right of the hole. When you feel good about the alignment, secure the collar to your flooring using stainless steel screws that are just long enough so that they will grab onto the subflooring.

Step 3: Soldering the Stop Valve

Make sure the water is off before starting this part. Put a bucket under the supply line and sever the line using tubing cutter. Make sure that you leave an inch or so on the pipe to attach the new stop valve.

After the valve has drained, remove the stem and handle since the soldering could damage it. Dry and clean the pipe as well as the valve inlet, then apply flux to each of them. Slip the stop valve over the supply line so that the valve points up.

From here, heat the stop valve joint using a torch. When the joint is hot enough to melt the solder, take the flame off and run that solder around the joint. All it takes is a drop of solder at the bottom of the joint to fill it.

Step 4: The Wax Ring and Setting the Bowl

There is a wax ring that sits on the collar; they should sit between the long, thread-up bolts that go into the collar. Press the ring down gently, flat-side down. Then, lift the bowl of the toilet over that flange, making sure that the holes line up with the closet bolts.

Don’t twist or rock the bowl, but press it down onto the ring until the bowl is resting on the floor. Don’t overtight as it could crack the bowl. If you notice unevenness, then use stainless steel washers to shim the bowl. Put a nylon washer over the bolts, hand-threading the nuts. Tighten a quarter-turn at a time, switching back and forth. Trim the bolts using a hacksaw and cover them with bolt covers.

Step 5: Installing the Tank

With the bowl in place, it is time to install the tank. Make sure that the tank-to-bowl washer on the outside bottom of the tank is seated, then fit small rubber tank washers into those tank holes on the inside, inserting tank bolts underneath.

Lower the tank gently to the back of the bowl; make sure to guide the tank bolts into the holes. Hand thread the nuts to get started, then alternate and check to ensure that the tank is level as you go. As with the bowl, don’t overtighten as it could crack. Make sure to connect the handle to the flapper chain as well.

Step 6: Seat Assembly and Supply Line Installation

Curve the supply line to sit between the stop valve and the tank supply. Hold the pipe, keep the flared end up, and mark a half-inch below the outlet, leaving just enough of the line to sit inside the outlet.

Cut the supply line, slipping a plastic nut, compression nut and compression ring onto the supply line in that order. Use Teflon paste on the outlet threads, seating the bar and the compression ring. Hand-tighten as usual, though you will need a wrench to tighten the compression nut.

Step 7: Final Touches

All that’s left to do is seat the assemble evenly over the bowl, tightening the nuts by hand. When you’re satisfied with positioning and tightness, it is time to turn the supply line back on. Open up the valve and give the tank a little time to fill.

If everything is working as it was meant to, all that is left is to check everything over to ensure there are no leaks. It is not uncommon to leave certain components less than tight, allowing water to drip through those connections from time to time. When the tank has filled, make sure to flush it six times.

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