Should a Toilet Flange Be Installed on Top of Tile?

Yes. On top of the finished tile floor, flush with it or barely proud of it, never sunk underneath. That’s the answer on every bathroom we tile, and it’s the same answer a plumber and a tile installer will give you if you catch them both on the same job site. The confusion comes from older homes where a flange got set before the flooring went in and nobody thought to plan around the tile thickness. Get the height wrong either direction and the toilet either leaks or rocks, and neither one is a small fix once the tile is grouted.

Where the Flange Actually Sits, Height by Height

The bottom of the flange lands on top of the finished floor surface, tile included. Not on the subfloor underneath it, not on the cement backer board before the tile goes down. On top of the tile itself. A little proud is fine, up to about a quarter inch. Sunk below the tile surface is the one position that never works.

Wax ring thickness is why the height matters this much. A standard wax ring is built to seal a flange sitting right at or slightly above the finished floor. Move that flange down even a half inch and the ring has to stretch across a gap it was never designed to bridge. Push it up too far, on the other hand, and the toilet base never fully seats against the floor.

Older ABS or cast iron drain stubs sometimes get left long on purpose during rough-in, cut to final height only after the tile is down. That’s the sequence we prefer on our own jobs. Guess the height before the tile goes in and you’re gambling on a tile thickness that hasn’t been decided yet.

What Goes Wrong When the Flange Sits Too Low

A leak, eventually, and not always right away. A wax ring stretched too thin to bridge a low flange doesn’t always fail on day one. It fails six months or two years later, after the wax has compressed and shifted under normal use. By then the leak is under the toilet base, soaking into the subfloor where nobody sees it until the flooring around the base starts to feel soft.

Flange extenders exist for exactly this problem. A stack of plastic spacer rings bolts onto the existing flange and brings the sealing surface back up to where it needs to be. Not a permanent structural fix in the strictest sense, but a legitimate one when a flange got set too low during a retile or a remodel. Two or three stacked rings covers most low-flange situations we run into on renovation work.

What Goes Wrong When the Flange Sits Too High

Rocking. A toilet that never quite sits flat no matter how many times it gets shimmed and re-caulked. High flange means the toilet’s horn sits above where the wax ring can properly compress, so the base hovers just enough to rock under weight. Caulking around the base hides the wobble instead of fixing it, and that’s a mistake we see a lot on jobs we get called to fix after someone else installed the toilet.

The fix is usually simpler than a low flange. A thicker wax ring, sometimes with a built-in horn extension, closes the gap without touching the flange itself. Shimming the toilet base helps with stability but does nothing for the seal underneath, so it should never be the only fix applied.

Who Sets the Flange Height: the Plumber or the Tile Crew?

Neither one, alone, and that’s the coordination gap where most of these mistakes happen. The plumber runs the drain and sets the rough flange height based on the subfloor. Then the tile crew builds up the floor with backer board, thinset, and tile, adding anywhere from three-eighths to three-quarters of an inch depending on the assembly. If those two trades never talk about final floor height before the tile goes down, the flange ends up wrong for whatever thickness the tile crew actually installed.

On our jobs, we ask for the flange to be left slightly high or the stub pipe left long before we ever start tiling. Once the finished floor height is locked in, cutting a pipe down to the right length takes minutes. Trying to raise a flange that’s buried under finished tile means pulling tile back up, and that’s a conversation nobody wants to have with a homeowner.

Re-Tiling Over an Old Flange

This is where most of our flange calls actually come from, not new construction. A homeowner is replacing vinyl or old tile with a new floor, and the existing flange was set to match the old flooring’s thickness. New tile plus new backer board is almost never the same height as what came out, and the flange doesn’t move on its own.

Thinner new floor than the old one means the flange now sits too high relative to the finished surface, and a thicker wax ring or horn extender usually solves it. Thicker new floor, large-format porcelain over a full mortar bed for example, means the flange that used to sit flush now sits low, and that’s when a spacer stack earns its keep. Either way, measure the actual finished floor height before ordering a wax ring. Guessing from the old flooring’s thickness is how these jobs go sideways. Our floor tile installation page covers how we handle build-up height on retile jobs generally, bathroom floors included.

Common Toilet Flange Installation Mistakes

Drilling through set porcelain for the mounting bolts instead of notching the tile before it goes down. Porcelain is hard, a drill bit walks on the glaze, and a cracked tile right at the toilet base is a bad look on an otherwise clean floor. Notch or pre-drill the tile piece before it gets set, not after.

Setting the flange on the subfloor and assuming the tile will just build up around it. Skips the whole point of matching flange height to finished floor, and it’s the single most common flange complaint we see in online plumbing forums from homeowners who got conflicting advice.

Reusing an old wax ring on a new install, or stacking two standard rings instead of using a proper extended one. Both moves save a few dollars up front and cost a callback later. A new ring is cheap. Subfloor plywood soaked for a year isn’t. Not sure which way your own job should go? Ask us and you’ll get a straight answer instead of a range.

Frequently Asked Questions

Can you install a toilet flange on tile?

Yes, and that’s the correct place for it. The flange bolts down through the tile into the subfloor beneath, with the sealing surface sitting on top of the finished tile, not below it.

Should a toilet be installed on top of tile?

The toilet base sits directly on the finished tile floor, same as the flange it bolts to. A wax ring between the two seals the connection, and shims fill any gap if the floor isn’t perfectly level.

What are common toilet flange installation mistakes?

Drilling through finished tile instead of notching it first, setting the flange to subfloor height and ignoring the tile buildup, and reusing a compressed wax ring on a new install. All three show up regularly on jobs we’re called to fix.

Should a toilet flange be flush with flooring?

Flush or very slightly proud, up to about a quarter inch above the finished tile. Sunk below the tile surface is the position that causes leaks.

Can a toilet flange sit on top of flooring?

That’s exactly where it belongs. On top of the finished floor, tile included, so the wax ring seals against a surface it was actually designed to meet.

What height should a toilet flange be after tiling?

Level with the top of the tile, or up to a quarter inch above it. Lower than that risks a leak, and much higher makes the toilet rock.

Do toilet flanges go on tile or subfloor?

Tile. The flange bolts through the finished floor into the subfloor structurally, but the sealing surface where the wax ring sits belongs on top of the tile, not buried under it.

Get the flange height right before the tile goes down and this whole problem disappears. Most of the calls we get about a rocking or leaking toilet trace back to a flange that was never coordinated with the finished floor height in the first place. Worth a five-minute conversation between whoever’s running the drain and whoever’s setting the tile, before either one shows up with materials already ordered.

Related Questions

• Does Tile Go Under the Toilet Flange, or Does the Flange Sit on Top?
• Can You Tile Over Tile?
• How to Cut Floor Tiles Around a Toilet?
• Can You Tile Over Linoleum?

Jordan Tile & Stone

Tile installation and repair across central Vancouver Island: Campbell River, Courtenay, Comox, Oyster Bay, Nanoose Bay, Parksville, Qualicum Beach and Nanaimo.

Phone: (250) 201-3891
Hours: Monday to Sunday, 7:00 am to 6:00 pm
Address: 4423 Patricia Rd, Oyster Bay, BC V9H 1B8