Can you tile over tub flange?

When remodeling a bathroom, you may want to replace the existing tub with a new one. This often requires removing the old tub and installing a new tub and tub surround. An important consideration when replacing a bathtub is what to do with the existing tub flange. The tub flange is the pipe that sticks up from the floor around the drain. It is designed to attach securely to the bottom of the tub to prevent leaks.

So, can you tile over an existing tub flange when installing a new tub? The short answer is yes, it is possible to tile over a tub flange, but extra care needs to be taken to ensure a watertight seal between the tile, tub, and plumbing. Improper installation could lead to leaks, water damage, and other problems down the road.

What is a Tub Flange?

The tub flange, also sometimes called a waste flange, is a pipe fitting that connects the bathtub drain to the drain pipe in the floor. It consists of a short vertical pipe attached to an elbow fitting. The top of the pipe has a rim or lip that sits flush with the surface of the floor.

Here are some key facts about tub flanges:

• Made of PVC, ABS, cast iron, or other material
• Diameter is usually 1 1/2″ or 1 1/4″
• Height above floor is typically 1″ to 1 1/2″
• Has threaded or slip-fit connection to drain pipe
• Rim creates a platform to support tub and make watertight seal

The flange both supports the weight of the tub and creates a tight junction to prevent leakage of water onto the bathroom floor. The lip of the tub fits over the tub flange rim and the tub drain tailpiece extends down into the drain pipe. Plumber’s putty, silicone, or other sealants are used to seal the gap between the tub and the flange.

Can You Tile Over an Existing Tub Flange?

When installing a new bathtub over an old one, you have three main options for dealing with the original tub flange:

1. Remove the old flange and drain completely and install a new flange
2. Leave the old flange in place and tile up to it
3. Extend the existing flange up to the new tile height

The easiest option is tiling over the old flange. However, this has some disadvantages:

• The new tub will sit higher than the old one
• The new tub will not make contact with the flange lip
• Grout and sealant will be needed to prevent leakage

Despite these downsides, tiling over the existing flange is a common technique. The key steps would be:

1. Detach the old tub from the flange
2. Remove adjacent flooring/substrate down to the flange
3. Build up thinset mortar to desired height
4. Install tile and tub, sealing tub to tile

If you want the new tub to sit at the same level and make proper contact with the flange, extending the old flange up or replacing it completely would be better options.

How to Extend a Tub Flange Up Through New Tile

Extending the original cast iron, PVC, or ABS flange up to the level of the new tile is one method to create a solid connection with the new tub. Here are the steps:

1. Remove old tub and adjacent flooring
2. Clean existing flange rim so new materials will bond
3. Dry fit new tub and mark desired height on flange pipe
4. Remove tub and cut flange pipe off at marked height using hacksaw
5. File cut end smooth and replace tub to confirm fit
6. Mix thinset mortar and apply to top of flange in layers until built up to tile height
7. Allow mortar to fully cure before setting tub
8. Install tile and tub, sealing gap between tub lip and flange

Extending the flange eliminates the gap that could lead to leaks. The mortar adds strength and stability as well. Take precautions not to get thinset or tools caught in the drain when building up the flange.

Tips for Extending a Cast Iron Flange

Cast iron flanges require a few special considerations:

• Use screwdriver to tap around cut line to break iron oxide seal
• Make cut with snap cutter tool to limit dust
• Seal cut edge with primer to prevent oxidation
• Use wire brush to rough up surface for mortar adhesion
• Apply multiple thin coats of mortar to prevent cracking

Patience is needed for mortar to cure fully between layers on cast iron. Rushing this step can lead to leaks.

PVC and ABS Flange Extension Tips

For plastic tub flanges:

• Use hacksaw, reciprocating saw, or handsaw to cut through PVC or ABS
• Sand cut edge smooth with file or sandpaper
• Roughen flange surface with sandpaper before mortar
• Prime before applying mortar if using ABS
• Build up to desired height in 1/4″ layers
• Allow several hours between mortar layers

Plastic flanges are much easier to cut and extend than cast iron. But take care to cleanly cut and prepare the surface.

Removing and Replacing Tub Flange

For maximum stability and seal with the new bathtub, removing the old flange entirely and installing a new one is advisable. This involves:

1. Detaching old tub and removing all flooring
2. Cutting out existing flange and drain pipe with reciprocating saw
3. Cleaning out pipe and preparing new drain connection
4. Gluing new flange to drain pipe at proper height
5. Allowing PVC glue to fully cure before setting tub
6. Installing tile and tub, sealing gap between flange and tub

Installing a new flange from scratch gives you the most control over positioning and height. However, cutting out the old drain and installing new connections is difficult. Avoid attempting this if you lack plumbing experience.

Hiring a plumber to replace the tub flange is often the best solution. They can ensure proper drainage slope and solid connections. This also prevents damage to existing plumbing hidden under the floor.

Tub Flange Replacement Tips

If attempting a full flange replacement, keep these tips in mind:

• Carefully cut out old flange to avoid damaging pipes
• Measure exact pipe size to get proper replacement flange
• Dry fit tub and set new flange height accordingly
• Glue new flange in place, allowing full cure time
• Make sure weep holes align with tile joints
• Attach tub/drain at correct orientation to line up with pipe

Rushing any step in replacing a tub flange can compromise the new drain. Going slow and testing fittings will ensure success.

How to Attach New Tub to Flange

Whichever approach you take for the tub flange, proper attachment of the new bathtub is critical for preventing leaks. Here are some tips:

• Clean flange rim thoroughly to remove grime
• Run a bead of silicone caulk around flange lip
• Set tub into mortar bed aligned with flange and drain
• Shim tub to proper height and slope with mortar if needed
• Use levels across tub rim to ensure it’s perfectly even with flange
• Tighten tub drain fitting firmly to “squeeze” tub lip to flange
• Fill any remaining gaps with silicone caulk
• Smooth out caulk with wet finger for finished look

The tub should make solid contact with the flange all the way around. Silicone seals the remaining small gaps. Avoid mortar contact with the drain opening during installation.

Tiling Around Tub and Flange

Careful waterproofing and tiling techniques are also important when tiling around a tub flange:

• Apply waterproofing membrane over tub lip and flange
• Cut membrane to allow drain access if needed
• Slope mortar bed toward tub and flange
• Use modified thinset for increased adhesion
• Avoid tiles smaller than 4” square, which can crack
• Use levelers to ensure even plane between tub and tile
• Grout using silicone for water resistance
• Caulk all tub/tile junctions and corners

Take extra time preparing the mortar bed and using quality setting materials. The tile installation should direct water runoff into the tub.

Tub Flange Tile Installation Tips

Here are some additional pointers for tiling around a tub flange:

• Leave 1/8” gap between tiles and flange
• Avoid laying tiles flat across flange lip
• Use tile edging trim if needed
• Grout all tile joints fully before caulking
• Apply silicone in corners with caulk gun for consistency
• Wipe away excess caulk with a damp sponge
• Use painters tape for clean caulk lines if desired

Getting a professional-looking finish takes practice and patience with all the sealing steps. But careful work will result in a watertight tub installation.

Conclusion

Tile can be installed over an existing tub flange when replacing a bathtub. However, the new tub may not sit as low or seal as tightly. Extending the old flange up to the tile level is one solution. For best results, removing the old flange entirely and installing a new one is recommended.

No matter the approach, take care to slope tiles, mortar, and waterproofing toward the tub. Caulking and grouting with silicone seals the gaps. This helps direct water runoff into the tub and down the drain. Pay close attention to detail at tub/tile/flange junctions to prevent moisture issues.

Replacing a bathtub and installing surrounding tile is an intermediate to advanced DIY project. Having previous plumbing and tiling experience helps ensure success. Hiring a professional for all or part of the project is wise for many homeowners. They can ensure proper drainage function while giving the new tub area a perfect finish.

Tub Flange Project Steps	Pro Tips
Remove old tub and flooring	Watch for hidden plumbing damage
Inspect and prepare flange	Sand rough surfaces; clean thoroughly
Dry fit new tub	Check orientation and level
Modify existing flange	Cut even; extend in layers; allow curing time
Set new tub	Shim if needed; caulk gaps
Tile around tub	Waterproof; use modified thinset; silicone grout
Finish plumbing	Tighten fittings; test for leaks

FAQs

Can I just place a new tub over the old flange?

It’s not recommended to simply set a new tub over an existing flange without building up to the level of the tub lip. This leaves gaps that require large amounts of caulk. Extending the flange or replacing it provides more support.

What’s the best way to attach the tub to the flange?

Run a bead of silicone caulk around the flange lip. Carefully lower the tub in place aligned with the drain pipe. Tighten the drain fitting to seal the tub lip to the flange. Fill any remaining gaps with additional caulk.

How do I keep the new tub level with an extended flange?

Check for level across the tub rim as you lower it onto the flange. If one corner is high, lift the tub and place thin mortar bed shims under the tub base at the low corner(s). Re-check for level and make any final adjustments.

Can I use regular thinset mortar for the tub surround?

It’s recommended to use a polymer-modified thinset when tiling around a tub. The adhesive properties provide a stronger bond to keep tiles firmly in place, preventing cracks or detachment from tub movement.

What size tile works best around a tub?

Tiles smaller than 4 inches square can crack over time. Larger tiles at least 4 by 4 inches or 6 by 6 inches adhere better and allow more precise leveling with the tub lip. Mosaic sheets can also be used if properly installed.