How To Install A Toilet

Need to know how to install a toilet? Here's how to replace a toilet that you previously removed. It's intended to follow the page about how to remove a toilet. It assumes that you are installing a toilet that is either a one piece or still-assembled two piece toilet, a close-coupled floor-mounted toilet.


For instructions on how to install a toilet that is new, you should keep reading for helpful hints. Be sure to read and follow the manufacturer's instructions. What? You threw them out?? No worries! If you don't have a copy of your toilet's specific installation directions, you can usually find them online. See Instructions, on my page Mechanics rules.

By the time I've pulled the toilet, I've pumped the water from tank and bowl, and confirmed that its supply valve (shut off), is working properly. I then lay the toilet on its back on a towel.

Assuming that you already accomplished the task that caused you to remove the toilet, we'll pick it up there.

Prep The Toilet Flange

Clean and dry the toilet flange and surrounding floor. First remove the heavy wax from the flange. My favorite scraping tool for this is an old reciprocating saw blade. I use them for cleaning toilet flanges and throw them away.

If the toilet flange is made of cast iron, after the wax is mostly cleaned off of the flange scour it with the tip of a cold chisel to remove any rusty scale that may allow water to seep under the new wax. Wipe the surface of the flange with a rag until the flange is clean and dry. Fold or replace the towel to create a clean dry surface.

Prep The Toilet

Use your hard plastic scraping tool to remove the old caulk from the base of the toilet. My favorite hard plastic scraping tool is a plastic laminate counter-top sample. There are usually some left over from jobs where that type of counter top is used. They're sturdy and don't leave marks on china. But be careful, because they can be sharp.

Use any tool you like to remove all of the old toilet wax and or plumbers putty from the underside of the bowl. Work till it is fairly clean; a “sheen” of old wax is no problem.

With the toilet on an absorbent rag tilt the toilet forward past its upright position, and then back again to its resting position. This removes any water that may drip out of the horn onto the floor, or worse, onto the wax toilet seal. Wet wax doesn't stick to anything. And water trapped between the china and the wax may never evaporate.

You want to install a toilet that's clean and dry onto clean, dry wax on a clean, dry flange! Clean and dry, that is how to install a toilet. To this end you must tilt the toilet, dry the horn and shift or change the towel until all stays dry. Then you'll know that no more water will drip onto the wax ring when you lift the toilet into position.

"Dry Set" The Toilet

Lift the toilet onto the flange so that the toilet bolts are protruding through the holes in the toilet base. This is your opportunity to see if the bolts are long enough to secure the bolt cap bases, washers and nuts. Now you'll also see if the toilet base will adequately cover any scars on the floor.

Make sure the toilet sits on the floor, not on the flange. There should be space for the wax. If there appears to be vary little space you might consider using a flat hornless wax ring. In general this is a chance to see that all is well without wasting a toilet wax ring when you install the toilet.

When you're satisfied that everything is good, pick the toilet up once again and set it aside. Check to see that the flange is still dry.

You're Ready To Install A Toilet

Prepare your wax ring by letting it come to room temperature, unless room temperature is ninety degrees.

You may now set the toilet wax onto the flange between the bolts, and finally set the toilet on the wax. Push evenly, straight down onto the wax. You should feel the resistance of the wax as it crushes into place.

Put the bolt cap bases, stainless steel washers and brass nuts into position and tighten the nuts going from one to the other till both are snugged. I use a nut driver for this. You may use a wrench but hold the handle well up toward the jaws close to the bolt. This will give you less leverage and allow you to better feel the tension you put on the bolts so as not to break the china.

Re-attach the water supply and open the valve.

Let the toilet fill until it stops. If all is well, flush the toilet several times to see if the floor remains dry. Once you're satisfied that you've installed the toilet properly, it's time to caulk it to the floor. I like the Red Devil brand siliconized water-based caulks. They stay flexible, don't shrink and clean up nicely.

Whew- you're done! Pat yourself on the back and take a shower.

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