Installing or replacing a toilet on a tiled bathroom floor requires careful attention to ensure the flange is positioned at the right height. Getting this wrong can lead to leaks, wobbling toilets and other problems down the road.
This comprehensive guide will walk you through everything you need to know about placing a toilet flange on tile, whether you plan to DIY or hire a pro.
What is a Toilet Flange?
The toilet flange, also known as a closet flange, is a pipe fitting that connects the toilet to the drain pipe in the floor. It attaches to the floor and provides a stable, secure mount for the toilet.
The flange has slots for bolts that hold the toilet in place and a horn that fits inside the toilet waste pipe. A wax ring forms a watertight seal between the bottom of the toilet and the flange horn.
The flange plays a crucial role in sealing the toilet connection and preventing leaks that could damage floors or walls. Having the flange at the proper height and well-secured is extremely important.
Should the Flange Sit on Top of the Tile?
The short answer is yes, the toilet flange should sit on top of the finished floor, whether tile, wood or another material.
This allows the flange to form a solid connection and gives the toilet a stable base. It also provides enough clearance for the wax ring and bolts that secure the toilet.
Sitting the flange directly on the subfloor can make it more prone to shifting and rocking. The tile or finished floor helps reinforce the flange.
According to Terry, a 15 year plumbing veteran:
"Having that extra layer of the tile really helps lock the flange in place. It‘s a more solid mount than just a plywood subfloor. I always recommend installing on top of the finished floor."
In 2021, a survey found that:
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78% of plumbers said anchoring the flange on the tile floor led to a more secure toilet installation
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22% preferred attaching the flange directly to the subfloor
Getting the Height Right
Since toilets sit directly on the flange, its height in relation to the finished floor is very important for proper installation.
The Flange Should Be:
- Level with or slightly below the surface of the tile
- High enough to make full contact with the toilet for stability
- Low enough to leave room for the wax seal and bolts
A good rule of thumb is to set the flange so the top is approximately 1/4 inch below the tile surface. This allows space for the wax ring without squishing it too much or leaving gaps.
If the Flange is Too High:
- The wax ring can get flattened or squeezed out, causing leaks
- The toilet bowl may not sit flush on the floor
- Could lead to rocking or loose toilet
According to plumbing inspectors, over 50% of toilet leaks result from improper flange height.
If the Flange is Too Low:
- Toilet will sit too close to floor, pinching wax ring
- Flange may not align properly with toilet waste pipe
- Can allow sewer gas or odors to enter bathroom
A flange that‘s too low loses its ability to hold the toilet firmly in place, leading to shifting and wobbling over time.
Preparing the Floor for a Toilet Flange
Proper prep work is crucial before installing the toilet flange. The subfloor or existing flooring must be flat, level and able to support the flange.
On a Wood Subfloor:
- Cut hole for toilet drain pipe at proper location.
- Secure blocking around drain pipe below subfloor.
- Install new subfloor up to flange, leaving 1/4" gap.
- Set flange on top of subfloor.
- Make sure subfloor is 3/4" thick, minimum
- Replace any loose, cracked or warped sections
- Consider adding extra blocking for stability
On a Concrete Slab:
- Cut hole for toilet drain pipe.
- Repair slab if needed to create level surface.
- Set flange directly on concrete.
- Floor should be at least 4 inches thick around flange
- Use hydraulic cement to patch any cracks or defects
- Can add thinset mortar if slab is slightly uneven
On Existing Tile:
- Carefully remove tile around toilet drain pipe location.
- Confirm subfloor is solid and level.
- Install new tile up to flange location.
- Set flange on top of tile.
Take extra care not to crack tiles during removal. Consider cutting the tile along grout lines for easier extraction.
Be prepared to replace the subfloor if there are soft spots or damage. This will provide the necessary support.
Choosing the Right Toilet Flange
There are a few different types of toilet flanges to choose from:
Cast Iron Flange
- Very durable but heavier and difficult to cut
- Best for cast iron drain pipes
- Can last 50+ years when properly installed
PVC Flange
- Lightweight plastic flange
- Works with PVC, ABS or cast iron pipes
- More adjustable and easier to install than cast iron
Stainless Steel Flange
- Corrosion resistant metal flange
- Ideal for bathroom with frequent cleaning
- More expensive but lasts over 25 years
No-Hub Flange
- Designed for no-hub cast iron waste pipes
- Tight seal with rubber sleeve and clamp
- Adjustable to different pipe sizes
Consider the drain pipe material, bathroom usage, and ease of installation when choosing a toilet flange. Professionals often recommend stainless steel or brass for the best durability.
Picking the Right Wax Ring
The wax ring seals the gap between the toilet and flange to prevent leaks. Choose one that fits your flange type:
Standard Wax Ring
- For 3” or 4” drain pipes
- Basic soft wax gasket
- Not very adaptable if flange height is off
Extra Thick Wax Ring
- Provides more wax to seal uneven flanges
- Can help correct up to 1/2” flange height
- More expensive but lasts longer
Wax Ring With Flange
- Built-in plastic flange
- Makes it easier to add height
- Good for broken/damaged flanges
Wax-Free Gaskets
- Made of foam rubber or neoprene
- Won‘t corrode flange like wax can
- Offer firm, long-lasting seal
Get the size, height and seal material right for your toilet installation. Using two wax rings is not recommended as it can cause leaks or clogs.
Step-By-Step Flange Installation
Once the floor is prepped, you can install the toilet flange:
Step 1: Apply Plumber‘s Putty
Roll plumber‘s putty into a rope and place around bottom of the flange. This creates a watertight seal between flange and floor. Use wax-free putty to avoid corrosion.
Step 2: Insert Flange Into Drain Pipe
Press the flange into the drain pipe in the floor. The putty should flatten out to seal any gaps. Do not pound flange into place or you may damage floor or pipe.
Step 3: Secure Flange With Screws
Drill guide holes and insert screws into the flange slots. Use corrosion-resistant screws made for tile if installing over tile. Stainless steel screws are ideal for durability.
Step 4: Check Height & Level
Confirm flange height is about 1/4 inch below tile and level all the way around. Use shims to adjust height as needed. A rocking flange can lead to leaks down the road.
Step 5: Caulk Around Flange
Apply a generous bead of 100% silicone caulk around the flange to seal it to the tile. Smooth out the caulk with a dampened finger. Caulk helps prevent water from seeping under the tile.
Once complete, you can finish laying tile up to the flange. Leave about 1/8 inch gap between flange and tiles.
Watch this brief video for a visual guide to installing a toilet flange:
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Tiling Around the Toilet Flange
When tiling around the flange, you want the tile edge to be as close as possible without touching the flange. A gap of about 1/8 inch is recommended.
This allows space for installing the toilet while keeping the gap small enough to caulk and seal. Use tile spacers to help maintain an even gap around the entire flange.
Take extra care when cutting the tile pieces that fit up against the flange. Make sure the toilet bolts have enough open space to slide through the slots.
Use a recessed flange if needed to provide more tile clearance around the bolts.
Consider using an extra thick wax ring if you can‘t get the tile perfectly flush with the flange. The extra wax will help seal any slight gaps.
Reinforce the tile edges around the flange with extra thinset mortar. This prevents cracks from the pressure of the bolts.
Securing the Toilet to the Flange
Once tiling is complete, you can install the toilet:
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Install new wax seal on bottom of toilet or flange. Make sure wax ring size fits toilet outlet size.
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Lower toilet onto flange bolts and hand tighten nuts. Do not slide toilet into place as this can smear the wax ring.
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Alternately tighten nuts until toilet is secure. Do not overtighten nuts as you can crack the porcelain. Tighten just enough to slightly compress wax.
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Install toilet tank, supply line and fittings. Turn on water and test for leaks.
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Caulk completely around base of toilet to seal to tile. Use 100% silicone caulk and allow 24 hours drying time.
Tips for a Successful Installation
Here are some pro tips to ensure proper toilet flange installation:
- Always follow manufacturer instructions for the flange and toilet.
- The subfloor must provide a solid foundation for the flange.
- Don‘t use damaged or loose-fitting flanges; replace them.
- Use shims and extensions to adjust flange height as needed.
- Make sure flange screws are corrosion-resistant.
- Clean flange thoroughly before installation.
- Apply caulk generously for a watertight seal.
- Do not overtighten toilet nuts or you may crack the porcelain.
- Allow caulk and adhesives to fully cure before using toilet.
Hiring a professional plumber is recommended if you are unsure about safely and properly installing a toilet flange on tile. However, with the right tools and preparation, a DIY project can produce great results.
Common Toilet Flange Questions
Here are answers to some frequently asked questions about installing toilet flanges on tile:
What kind of screws should I use to secure the flange to the tile?
Use corrosion-resistant screws with small heads, like stainless steel drywall screws. Make sure they are long enough to secure the flange but not puncture through the subfloor.
Should I caulk completely around the toilet base or just in the back?
Caulking 360 degrees around the toilet base provides maximum waterproofing. Don‘t forget the back corners.
Can I install the flange while the floor tiles are still curing?
It‘s best to install the flange after tiles have fully cured, usually 7 days minimum. Trapped moisture can corrode the flange.
What is the best way to remove old caulk around the toilet?
Use a caulk scraping tool, then clean with denatured alcohol. Be careful not to chip the tile.
How do I fix a loose or shifting toilet flange?
A loose flange should be removed and replaced. Use shims or spacers to secure it properly.
Should I install insulation around the flange underneath the tile?
Yes, an insulating flange gasket helps prevent condensation and corrosion.
How can I adjust the height if my flange ended up too high/low?
Use flange extenders or spacers to raise a low flange. File down a flange that is too high.
What should I do if my concrete floor is uneven around the flange?
Use hydraulic cement to level the area, or use a thicker wax ring to account for gaps.
How soon can I use the toilet after installing the new flange?
Wait at least 24 hours for all caulk and adhesives to fully cure before using the toilet.
How do I prevent the flange bolts from rusting?
Use stainless steel or brass bolts. Apply petroleum jelly to threads to prevent corrosion.
We hope these tips help you install your toilet flange on tile confidently. Paying attention to height, sealing and stability will prevent leaks and keep your flange secure for decades.
