What is a shower flange and what does it do?

A shower flange is the waterproof lip at the edge of a shower base where the walls meet it, and its job is to make the wall finish overlap the base so water runs back onto the pan instead of behind the wall. Ella custom shower bases carry a tile flange for exactly that reason, and where a base or tub has no lip the same flexible glue-up strip described in What Is a Tile Flange on a Walk-In Tub? is bonded on at installation. This page explains what the flange does, the two forms it takes on Ella showers, how the glue-up version goes on, and how it differs from the threshold at the front of the base.

What the Flange Does

Water in a shower runs down the walls and lands on the base. Where the wall finish meets the base edge, the joint has to be arranged so that water lands on the pan and drains away rather than finding the seam and getting behind the tile or the panels. The flange is the piece that makes this happen. It stands up from the base edge against the wall, the tile or wall panel comes down over it and onto the edge, and every joint is sealed with 100 percent silicone. Water running down the wall meets the flange and is turned back onto the pan. It is a small detail, and it is the one that keeps a tiled enclosure dry for years.

The same principle applies to Ella walk-in tubs, which have a flat deck edge with no built-in lip. There the flange is a rustproof, waterproof strip about 5 inches tall, glued to the tub edge with 100 percent silicone so it overlaps the edge by about 2 inches, and My Tub Has No Tile Lip. Which Flange Do I Use? walks through that installation. For a shower base the same flange approach applies, and the flexible strip can go on after the base is set.

Two Forms of Flange on an Ella Shower

Molded flange on a custom base. When Ella makes a custom size shower base, the base has a tile flange, which is why a custom base works well in a shower where the walls will be tiled. The flange is part of the base as it arrives, so the tile installer simply runs the wall tile down over it. Shower Bases and Walls: Roll-In, Seat, Custom Sizes, Thresholds and Wall Systems lists the custom base choices, including drain placement on the left, right or center.

Flexible glue-up flange. Ella's Flexible Glue-Up Tile Flange kit, listed as FlangeBand, is a 124 inch strip of 4 inch wide flexible membrane with a 1 1/4 inch adhesive strip, plus a spreading spatula, an alignment guide and alcohol wipes. The strip is a durable, waterproof adhesive fabric with a siliconized membrane that reacts and chemically bonds to the 100 percent silicone you apply, and that bond holds through general expansion and contraction and routine floor settling. Because the membrane is flexible, it follows the small movement between a fixture and the wall that a rigid plastic lip cannot. The kit is also sold in bulk for contractors. The second video on this page shows the flexible flange going on around a shower base, and notes that Ella strongly recommends it for tub installations as well.

How the Glue-Up Flange Goes on

The first video walks through the kit step by step, and the order of work is the same for a base or a tub.

1. Mark the strip position on the walls so the strip lines up. In a two-wall enclosure the base is set temporarily in its working position, the alignment card rests on the ledge against the wall, and each wall is marked above the ledge and where the base ends. In a tighter three-wall enclosure the marks are calculated from the expected ledge height so the base does not have to be slid into place first.
2. Clean the edge with the alcohol cleaning cloths in the kit.
3. Apply 100 percent silicone to the strip and bond it so it overlaps the base edge, spreading the sealant with the spatula tool.
4. Run the tile or wall panel down over the flange and onto the edge, then silicone every joint.

Set the base first and connect its drain before the walls go on, because both the flange and the wall finish depend on where the base finally sits. The strip is reversible, and which colored side faces out depends on whether the fixture already has an integral flange, so a custom base with its own molded lip and a flat-edged tub are handled differently with the same kit.

A Flange Is Not a Threshold

Two different edges of a shower base get confused in searches. The flange runs along the wall sides and keeps water from getting behind the walls. The threshold is the curb across the front of the base that you step over. On an Ella custom base the front threshold is either 2 inches or 4 inches, and that choice sets the inside basin depth: a 4-inch threshold gives approximately 2 inches of depth and a 2-inch threshold gives approximately 0.25 inch. A base can have a tile flange on its wall sides and a low threshold on its front at the same time, and one never replaces the other.

Other Flanges You Will Hear About

The word flange turns up elsewhere on Ella products, so check which part a list means before you order. The swivel tray on the stainless inward-swing door deck mounts to a plastic mounting flange near the door, and both the tray and that flange are replaceable accessories, as What Are My Options If My Swivel Tray Broke or Does Not Fit? covers. That flange holds a tray and has nothing to do with waterproofing. The tile flange for a walk-in tub is an aftermarket option that ships separately by parcel carrier rather than in the crate, so do not report it missing on delivery day. Support records it under the part code EB-FLANGE, and including your model when you request one makes sure the right length ships, since longer strips are listed for larger models. The ShaK is the one tub not designed to be tiled in directly, so talk with technical support before planning tile around one. For any flange question, open a ticket at ellasbubbles.com/support with your model, a sketch of the enclosure with wall lengths in inches and a photo of the edge at the wall, or call (800) 480-6850.

Watch: Walk-In Tub Accessories to Enhance Your Experience | Ella's Bubbles with chapters and a full transcript.

Related Guides

• What Is a Bathtub Flange and What Does It Do?
• 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

Common Questions