The toilet flange is the ring on the floor that connects the toilet to the drain. It should sit on top of the finished floor. When you tile over an old floor, the finished surface rises by the thickness of the tile and mortar, and the flange ends up below it. A toilet set on a low flange leaks, rocks and eventually stains the ceiling below.
The fix is to raise the flange, and the right method depends on how far. This guide covers height, extension rings and the choices when the flange is damaged.
The target height
The top of the flange should be flush with, or up to a quarter inch above, the finished floor. If it sits below, the wax seal has to bridge a gap it was not made for. Measure after the tile is set, not before.
Use a straightedge across the flange and a tape measure to the floor. If the flange is more than a quarter inch below the tile, add a spacer.
| Gap between flange and tile | Fix |
|---|---|
| Up to about a quarter inch | Thicker wax ring or extra-thick seal. |
| A quarter to three quarters of an inch | Flange extension ring (spacer) under or over the flange. |
| More than about an inch | Replace the flange with a deeper or repositioned one. |
| Cracked or rusted flange | Repair ring or full replacement. |
Fitting an extension ring
Remove the old toilet and wax
Clear the flange of wax and debris.
Dry fit the ring
Set the extension ring on the flange and align the bolt slots.
Seal and fasten
Apply a bead of sealant if the product calls for it, then fasten with the supplied screws into the subfloor, not just into the tile.
Install the bolts and seal
Slide new closet bolts into the slots, then set the wax ring and the toilet.
Do not stack many rings to make up a big gap. Stacked rings can leak between layers. If the gap is large, replace the flange so it sits at the right height.
Choosing a flange and a seal
Flanges come in PVC, ABS, cast iron and brass. Match the new flange to the pipe it attaches to. PVC and ABS do not glue to each other without the right cement or an adapter. Cast iron needs a different connection, often with a caulked or no-hub fitting.
Wax rings are the traditional seal. Rubber and foam seals are an alternative and tolerate small misalignment better. Some come in extra-thick versions for flanges that sit slightly low. Read the box. A seal that is too thick on a flange that is too high will not compress properly.
Check the floor before you set the toilet
Press on the floor around the flange. It should feel solid. A soft spot means rot, and the toilet will rock no matter how well the flange is set. Look at the ceiling below for stains. If the subfloor needs repair, do it before the tile goes down, not after.
What the plumbing code expects
The California Plumbing Code (UPC-based) expects the toilet flange to be anchored to the floor and the toilet to be bolted to it, with a watertight seal between them. A flange that floats on tile does not meet that expectation, which is why we anchor to the subfloor.
Floors and flanges in Saratoga homes
Saratoga has older homes near the Village along Big Basin Way and newer homes elsewhere. Older bathrooms may have cast iron flanges rusted into the pipe, and later remodels may have layers of tile, mortar and subfloor.
Practical meaning: a bathroom that has been tiled twice can leave the flange far below the new surface. Check the subfloor around the flange for soft spots before you set anything. A soft floor means water has been getting out.
The City of Saratoga building division is the contact for permits if the project involves moving the toilet or changing the drain. San Jose Water Company supplies most Saratoga homes, and its groundwater reads roughly three times harder than Valley Water imported surface supply, which leaves scale in the toilet fill valve over time.
Sources: San Jose Water Company annual water quality report. City of Saratoga building division.Anchoring on tile
Never anchor the toilet or the flange into the tile alone. Tile cracks. Fasten the flange to the subfloor with corrosion-resistant screws, and use closet bolts that rise through the flange slots. The toilet's weight then rests on the flange and the floor, not on the tile edges.
Drilling the tile for a flange screw needs a masonry bit and care. If you are installing a flange after the tile is set, pre-drill carefully to avoid cracking.
When to call a plumber
Call when the flange is cracked, when the drain pipe under it is damaged, when the subfloor is rotten or when the toilet has leaked for a while. A plumber can cut out the old flange, repair the pipe and set a new one at the right height. Our toilet repair page lists what we do.
If water has been leaking at the base, ask about leak detection to check for hidden damage. For a new bathroom or a changed layout, see plumbing installation. Los Gatos homeowners can read the Los Gatos page.
Common mistakes
Setting the flange before the tile is the classic one. Leave the final height until the floor is done. Another is using a wax ring that is too thin for the gap. A third is tightening the toilet bolts unevenly, which cracks the porcelain. Alternate sides and stop when the toilet no longer rocks.
Plumbing problem right now?
Call the 24/7 line and a dispatcher will plan the next step with you.
Questions Saratoga Homeowners Ask
Flush with the finished floor, or up to a quarter inch above it.
Not as a fix for a large gap. A spacer or a deeper flange is better.
No. Fasten it to the subfloor.
A repair ring may work. A badly damaged flange needs replacement.
Usually only if you move the toilet or change the drain. Ask the City of Saratoga building division.