What Is a Shower Flange and What Does It Do?

A shower flange is a thin waterproof strip bonded to the top edge of a tub or shower base where it meets the wall, so the tile or wall panels can come down over it and shed water back into the fixture instead of behind the wall. Ella walk-in tubs and shower bases have a flat edge with no molded lip, so the flange is added at installation, and Ella's flexible glue-up kit does the job on a tub deck and on a shower base alike. The tub version of the same part is defined in What Is a Tile Flange on a Walk-In Tub?; this page covers what the flange does, what the kit contains, how it goes on, and the other parts of a tub that are also called a flange.

What the Flange Does

Think about where splash water goes when you use a hand shower in an alcove. It runs down the wall, reaches the joint where the wall meets the tub or base, and either turns back into the fixture or slips behind it. A molded bathtub has a built-in lip that steers water back. Ella fixtures do not, by design, so the flange is that lip, added on site. It bonds to the edge of the tub or base with 100 percent silicone, stands up the wall, and the wall finish overlaps it. Water that runs down the tile hits the flange and drops back into the tub. Every joint is then caulked with silicone so nothing gets past the layers.

When that layering is missing, the symptom is a tub that leaks at the corners or along the wall line when filled or splashed while the door itself stays dry. Tile that stops above the flange, a flange that does not overlap the edge, or corners left uncaulked all show up the same way, and Why Does My Tub Leak at the Corners or Wall When Filled? walks through how to tell that finishing gap from a leak under the tub.

What Ella Supplies

The installation manual describes the requirement generically: any rust-proof, waterproof strip 1/8 inch or 3/16 inch thick, in acrylic, thin stainless steel or fiberglass, about 5 inches tall, glued to the tub edge with 100 percent silicone so it overlaps the edge by about 2 inches. The current Ella part that fills that role is the Flexible Glue-Up Tile Flange kit, listed as FlangeBand and recorded by support under the part code EB-FLANGE. The kit contains:

• A 124 inch strip of 4 inch wide flexible membrane with a 1 1/4 inch adhesive strip along it.
• A spreading spatula for the silicone.
• An alignment guide card for marking the walls.
• Alcohol wipes for cleaning the edge before bonding.

The strip is reversible, and which colored side faces out depends on whether the fixture already has an integral flange. The membrane matters more than it looks. Because it is flexible, it follows the small movement between the tub and the wall through expansion, contraction and routine floor settling, which a rigid plastic lip cannot do. The 124 inch length suits most Ella tubs in a standard three-wall 60 inch alcove, and longer strips are listed for larger models such as the Big4One, TransferXXL, LayDown72, Escape and Big4Two. The flange ships separately by parcel carrier rather than in the crate, so it is not missing if it is not in the box with the tub. When you request one through where you purchased the tub or the team at (800) 480-6850, include your tub model so the right length ships. If you are unsure which length you need, My Tub Has No Tile Lip. Which Flange Do I Use? explains how to measure the wall run.

How to Install a Flange

The installation video shows the whole sequence on a shower enclosure, and the same steps apply to a walk-in tub deck. In brief:

1. Finish the fixture first. Level the tub with every leg bearing on the floor and complete the pre-installation water test before any wall finish goes on. For a shower base, the flexible strip can go on after the base is set.
2. Mark the strip position on the walls. The video shows two methods. In a two-wall enclosure, set the tub or shower floor temporarily in its working position, rest the alignment card on the ledge against the wall, mark each wall at least twice, mark where the fixture ends, then remove the fixture and draw the horizontal and vertical lines through the marks. In a tighter three-wall enclosure, work out the height of the strip's upper edge from the anticipated height of the ledge above the finished floor, so the lines can be drawn without sliding the fixture in and out.
3. Measure the run. Measure the total length of edge that meets a wall, the back plus each end, at deck height, and match it to the kit length.
4. Clean and bond. Wipe the edge with the alcohol tissues from the kit, apply 100 percent silicone, and press the strip on so it overlaps the edge. The video explains that the siliconized membrane reacts with and chemically bonds to the silicone, which is what gives the joint its strength.
5. Finish the walls over it. Run the tile or wall panel down over the flange and onto the deck, then silicone every joint: tub to wall on all three sides, each corner, the extension panel to tub line and the end panel to wall line.

Existing wall tile that is sound and properly sealed can stay; your installer confirms its condition. One model is the exception to all of this: the ShaK is not designed to be tiled in directly, so talk with technical support before planning tile around a ShaK.

Other Parts on a Walk-In Tub Called a Flange

Flange is also the word for any collar that sits over the edge of an opening, so you will meet it in two other places on an Ella tub, and neither has anything to do with the wall seal.

• The swivel tray flange. The patented 360 degree swivel tray mounts through a threaded fitting near the door, and the plastic mounting flange at that fitting is a replaceable accessory. The tray itself is 8.5 by 8.5 inches with a 2 inch pin on one corner that slides into the fitting and is secured with a screw-on cap. If the flange or tray cracks, What Are My Options If My Swivel Tray Broke or Does Not Fit? covers which models take the tray and what to photograph.
• The flange of a control or fitting. When an installer cuts a hole in the deck for a push control, switch or aromatherapy canister, the flange of that part sits over the cut edge. It hides the fine hairline lines that sometimes appear in the finish around a fresh cut, which Ella's technical support has never seen extend, as explained in Hairline Lines Around a Hole Cut in the Tub Deck.

If a question about a flange comes up on install day, say which one you mean. For the wall flange, open a ticket at ellasbubbles.com/support with your model, a sketch of the alcove with wall lengths in inches and a photo of the tub or base edge where it meets the wall, and your Ella dealer or the team at (800) 480-6850 will confirm the kit and how to place it.

Watch: Installing a Glue-Up Tile Flange: Step-by-Step | Ella’s Bubbles with chapters and a full transcript.

Related Guides

• The Glue-Up Tile Flange Kit: What Is in the Box, Which Length to Choose, Which Colored Side Faces Out, and Whether It Goes On Before or After Drywall
• Tile Flange, Caulking, and Finishing the Walls Around Your Walk-In Tub

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