What tub edge details keep water from getting behind alcove tile?

Ella walk-in tubs have a flat deck edge with no molded tile lip, so there are three details to confirm before the first tile goes up: a glue-up tile flange bonded to the deck edge with 100 percent silicone so it overlaps the edge, wall tile that comes down over the flange and onto the deck rather than stopping above it, and a bead of 100 percent silicone at every joint, including the corners. What Is a Tile Flange on a Walk-In Tub? defines the part; this page is the pre-tiling checklist for an alcove, with the figures, the sequence and the mistakes that let water behind the wall.

Why There Is No Lip to Tile over

A standard bathtub carries a molded lip that the tile hangs over. An Ella walk-in tub does not, by design: the deck edge is flat, and the water barrier at the wall is a flange added at installation. The installation manual describes it generically. Any 1/8 inch or 3/16 inch rust-proof, waterproof strip will do the job, whether 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. Ella's own part is the Flexible Glue-Up Tile Flange kit, a 124 inch strip of 4 inch wide flexible membrane with a 1 1/4 inch adhesive strip, supplied with a spreading spatula, an alignment guide and alcohol wipes. The flexible membrane follows the small movement between tub and wall that a rigid lip cannot, and the embedded video shows why: the strip's siliconized edge reacts with and chemically bonds to the silicone sealant, so the seal holds through expansion, contraction and routine floor settling. The video also shows the kit contents and how the alignment card is rested on the tub ledge to mark the strip position on each wall with the tub set temporarily in its working position. My Tub Has No Tile Lip. Which Flange Do I Use? covers the part choice in more depth.

Two model notes. The 124 inch kit suits most Ella tubs in a standard three-wall 60 inch alcove, and longer strips are listed for the Big4One, TransferXXL, LayDown72, Escape and Big4Two, so give your model when you request one. The ShaK is the exception: it is not designed to be tiled in directly, so talk with technical support before planning tile around a ShaK.

The Checklist to Confirm Before Tiling

1. The tub is level with every leg bearing on the floor. An unlevel frame opens gaps at the wall line and at the door, and no flange closes a gap that keeps moving.
2. The pre-installation water test is done. Fill and hold the tub with the access panels open and check the unions, fittings and drain before any wall is closed, because fixing a leak behind finished tile is far more disruptive.
3. The flange is on hand. It ships separately by parcel carrier, not in the crate with the tub, so do not report it missing on delivery day. Support records it under the part code EB-FLANGE.
4. The length is right. Measure the total run of tub edge that meets a wall at deck height, the back plus each end, and match it to the kit lengths.
5. The tub edge is cleaned with the alcohol wipes in the kit, and the flange is bonded with 100 percent silicone so it overlaps the tub edge. The strip is reversible, and which colored side faces out depends on whether the fixture already has an integral flange.
6. The wall finish is planned to come down over the flange and onto the deck. The tile or panel must never stop above the flange.
7. Every joint gets 100 percent silicone: tub to wall along 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, and your installer confirms its condition. Wall panels and surrounds follow the same overlap rule as tile.

Where Water Gets Behind Tile When a Detail Is Missed

Most reports of a tub leaking at the corners while the door stays dry turn out to be finishing gaps rather than tub defects. The common ones are no flange at all, or a flange that does not overlap the tub edge; tile or panels that stop above the flange instead of overlapping it; and corners or the extension panel line left uncaulked, or caulked with something other than silicone. A simple test separates these from a leak under the tub. Dry everything, fill the tub with the door closed and let it stand. If the corners stay dry until you splash or use the hand shower, the water is coming over the deck edge at the wall line. If water appears on the tiles below the panel or on the floor while you bathe, open the access panels and trace it under the tub instead, starting with the unions at the pump and heater, the air tube fittings, the push button gaskets and the drain elbow. Why Does My Tub Leak at the Corners or Wall When Filled? walks through that diagnosis in order.

Corner and Single-Wall Layouts

Not every Ella tub sits in a full three-wall alcove, but none is meant to be a standalone tub. Every model is designed to sit against at least one wall along its long side, so there is always a back wall to seal. In a corner or single-wall layout, treat every wall the tub touches the way an alcove wall is treated: bond the flange to the deck edge along that run, bring the wall finish down over it, and silicone every joint. The ends that face the room are closed with an end panel, and the hand shower stays below deck height and aimed at the tub wall. How do I contain splash behind a walk-in tub outside an alcove? works through the water paths for those layouts one at a time.

Who Does This Work

Ella manufactures the tub and does not perform installation, so the flange, tile and caulking are your licensed contractor's work. Ella supports that contractor at no charge for the life of the tub with installation manuals and spec sheets for every model, phone and email technical support, and live video chat on request. If you need help finding someone, your Ella dealer or the team at (800) 480-6850 can connect you with installers in Ella's nationwide network. Who Installs My Walk-in Tub? Hiring a Licensed Contractor and How Ella Supports Them explains how that support works. After the walls are finished, keep the caulk line between the tub and the wall in good condition and re-caulk if it cracks or pulls away.

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

Related Guides

• How Do You Install a Tile Flange on a Tub or Shower Base?
• 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
• What Is a Bathtub Flange and What Does It Do?

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