Toilet Flange Height: Set It to the Finished Floor

Set the toilet flange to the finished floor. A flange manufacturer’s best-practices page puts the height on top of or even with the finished floor. The finished floor is the top of your new tile or flooring, not the old subfloor. That’s the answer on toilet flange height. The Tennessee residential code section on floor-mounted fixtures sets no flange height, so the manufacturer’s wording is the reference.

A flange left below the new floor may keep the toilet from sealing. And once the tile’s down, correcting it can be harder than planning it before. Settle the flooring first. Then ask the design team and the plumber to plan the flange around it.

What Should Toilet Flange Height Be on a New Floor?

A flange manufacturer’s best-practices page says the flange should sit on top of or even with the finished floor. That’s the height to plan for. Not level with the subfloor, and not sitting under the tile. The toilet stands on the finished surface, so the flange gets set to that surface.

Finished floor means the surface the toilet will stand on once the work is done. That’s the tile and whatever sits under it, or the flooring and its underlayment. Which makes where the flange sits a relationship, not a figure to memorize. It’s tied to a floor that may not be down yet when the question comes up.

That height line comes from a flange manufacturer’s best-practices page on installing a toilet flange. It names no inch figure. The finished floor is the measure.

Why Does a New Floor Change Where the Flange Sits?

New tile raises the floor. So can underlayment, and so can a heating mat. A flange that was set to the old floor can end up below the new one, even though nobody moved it. The floor came up around it. That’s why the flooring choice and the flange belong in the same conversation.

Guthrie’s post on a heated floor makes the point: lift the floor and the flange’s height relative to the tile changes with it.

The manufacturer’s page spells out both misses. Too low, and the wax ring may not seal properly: leak paths can form because the flange isn’t at the correct height to accept the horn at the bottom of the toilet. The page says an extra-thick wax ring or a flange extender may be needed to make up the difference.

Too high, and the toilet may rock, which stresses the seal. Which correction suits a given floor is the plumber’s call.

What the Code Text Covers and What It Leaves Out

Section P2705.1 of the 2018 Tennessee Residential Code covers floor-mounted fixtures. It says they shall be secured to the drainage connection and to the floor. It adds that where fixtures come in contact with walls and floors, the contact area shall be water tight. That’s fastening and a water-tight contact area.

You can read that section in the 2018 Tennessee Residential Code, as published by a code-publishing site. That site labels the code as Tennessee’s adoption, with amendments, of the 2018 International Residential Code.

What the section doesn’t do is set a flange height. There’s no figure in it, and no instruction about where the flange sits relative to the floor. That’s why the manufacturer’s wording carries the height. Which plumbing code and edition apply at your address is for the local building department to confirm.

Questions to Settle Before the Floor Goes In

Bring these to the design team and the plumber while the floor is still a decision.

• What will the finished floor be, counting the tile, any underlayment and any heating mat?
• Who sets the flange to that finished floor, and when in the schedule?
• Is the plan on top of the floor or even with it, and which wax ring suits that?
• Will the flange bolt slots be covered before the tile or flooring goes down, as the manufacturer’s page advises?
• Is the toilet’s location changing?

Guthrie’s post on toilet clearance notes that moving a toilet’s drain after the floor and walls are finished can mean opening them again, so the toilet’s spot is worth settling early.

Frequently Asked Questions About Toilet Flange Height

Should the toilet flange be flush with the floor?

A flange manufacturer’s best-practices page puts the height on top of or even with the finished floor. So even with the finished surface sits inside what the page describes. The part to watch is which floor you mean. Even with the old subfloor can leave the flange below the new tile.

For a flange that ends up too low, the page says an extra-thick wax ring or a flange extender may be needed to make up the difference.

What happens if the flange sits too low?

Per the manufacturer’s best-practices page, the wax ring may not seal properly. Leak paths can form because the flange isn’t at the correct height to accept the horn at the bottom of the toilet. A flange set to the old floor can land low once the new tile is down, and no one has to touch the flange for that to happen. The finished surface moved.

What happens if the flange sits too high?

Per the manufacturer’s best-practices page, the toilet may rock, and that rocking stresses the seal. Note that the page’s height line is on top of or even with the finished floor, so a flange resting on the floor surface isn’t the miss. Judging whether a flange sits too high on a given floor is a question for the plumber, and it’s worth asking before the toilet goes back in.

Can the flange height be corrected after the tile is down?

Sometimes. For a flange that ends up too low, the manufacturer’s best-practices page says an extra-thick wax ring or a flange extender may be needed to make up the difference. The plumber decides which one fits the floor in front of them. But planning the flange with the flooring choice keeps the question from coming up at all, which is why the floor gets picked first.

Will Guthrie help me plan the floor around the toilet?

Guthrie’s design team helps homeowners get the most out of a bathroom layout. It guides them through the selections, from the layout to tile, flooring and plumbing fixtures. The Pleasant View showroom lets you see materials in person, so a flooring choice stops being abstract. You can visit the showroom or schedule a consultation. Bring the floor you’re weighing and the toilet’s location to that conversation.

Bring the Tile and the Toilet’s Location to the Showroom

At Guthrie’s Pleasant View showroom, you can see materials in person, from cabinetry and countertops to plumbing fixtures.

So what should toilet flange height be? On top of the finished floor, or even with it, per the manufacturer’s best-practices page. That puts the flooring decision first. You can’t set a height to a floor nobody has chosen yet.

If a bathroom remodeling project is on your list, you can visit the Pleasant View showroom to see materials in person, or schedule a consultation to get started.

When the floor and the flange belong on the same plan, talk with Guthrie’s design team about your bathroom floor and toilet location.