What is a shower flange and what does it do?

A shower flange is a thin waterproof strip bonded along the top edge of a shower base or tub where it meets the wall, so the tile or wall panels overlap it and water running down the wall is sent back into the shower instead of behind the wall. It is also called a tile flange, a tiling flange, a glue-up flange or a flange band. Ella walk-in tubs have a flat deck edge with no built-in lip, and the same glue-up flange approach applies to a shower base, as What Is a Tile Flange on a Walk-In Tub? explains for the tub side. This page covers what the flange does, what the Ella kit contains, how the strip goes onto shower walls, how tile or panels are finished over it, and the other Ella parts that share the name.

What the Flange Does, and What Happens Without It

Think of the wall line as three layers. The flange bonds to the edge of the base or tub with 100 percent silicone and stands up against the wall. The wall finish, whether tile or a panel, comes down over the flange and onto the deck. Then every joint is caulked with silicone. Water that runs down the wall meets the finish, then the flange, and is directed back into the fixture. Remove any one of the three layers and splash water has a path downward at the wall line.

That is why a leak at the corners is so often a finishing problem rather than a defect. When a tub leaks at the corners or wall when filled, and the door itself stays dry, the usual causes are no flange at all, a flange that does not overlap the edge, tile or panels that stop above the flange instead of overlapping it, or corners left uncaulked. Why Does My Tub Leak at the Corners or Wall When Filled? walks through that diagnosis, and the fix is a bead of 100 percent silicone at every joint once the flange and the overlap are confirmed.

A flexible flange does one more thing a rigid lip cannot. Because the Ella membrane bends, it follows the small movement between the fixture and the wall during general expansion and contraction and routine floor settling, so the seal stays tight where a hard plastic lip would eventually open a gap.

What Is in the Ella Glue-Up Flange Kit

Ella's own kit, listed as FlangeBand and recorded by support under the part code EB-FLANGE, is a 124 inch strip of 4 inch wide flexible membrane with a 1 1/4 inch adhesive strip, a spreading spatula, an alignment guide and alcohol wipes. The first video on this page shows the kit laid out: a roll of Sealux to fit your requirements, alcohol surface cleaning cloths, the custom spatula tool and the strip alignment card. Sealux is a patented flexible flange made of a durable waterproof adhesive fabric and a siliconized membrane. When 100 percent silicone is applied to the pink silicone-based strip, the membrane reacts and chemically bonds to the sealant, which is what gives the joint its strength. Contractors who fit many showers can get the material in bulk form.

The flange is strongly recommended for Ella installations, but the kit is not the only option. Any 1/8 inch or 3/16 inch rust-proof, waterproof strip will do the job on a tub: acrylic, thin stainless steel or fiberglass, about 5 inches tall, glued to the edge with 100 percent silicone and overlapping the edge by about 2 inches. The flexible kit is simply the version that moves with the house.

The 124 inch kit 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. Two things to know when you order it. The flange ships separately by parcel carrier, not in the crate with the tub, so do not report it missing on delivery day. And the ShaK is not designed to be tiled in directly, so talk with technical support before planning tile around a ShaK. When you request a kit through where you purchased or the team at (800) 480-6850, include your model so the right length ships.

Putting the Strip on a Shower Base

The first video shows the glue-up flange being installed on shower walls, and the second shows the same flexible flange working around a shower base. On a shower base the flexible strip goes on after the base is set. The first step is to mark the strip position on the walls so the flange is aligned correctly, and the video shows two ways to do that.

1. For a two-wall enclosure, place the shower floor or tub temporarily in its working position. Rest the alignment card on the ledge against the wall and mark each wall at least twice at the card's height above the ledge, then mark where the floor ends. Remove the base and draw horizontal lines through the upper marks and vertical lines just outside the end marks.
2. For a tighter three-wall enclosure, you do not have to slide the base in. Work out the height of the strip's upper edge from the anticipated height of the ledge above the finished floor, and mark the walls from that figure.
3. Clean the edge with the alcohol cloths from the kit, then bond the strip with 100 percent silicone so it overlaps the edge. The strip is reversible, and which colored side faces out depends on whether the fixture already has an integral flange.

On a walk-in tub, wall finishing should only begin after the pre-installation water test and the leveling check, because fixing a leak behind finished tile is far more disruptive than finding it with the panels off. The same patience pays off on a shower: have the base set and the drain connected before the walls go on. If your fixture has no tile lip at all, My Tub Has No Tile Lip. Which Flange Do I Use? explains that this is by design and how to measure the total run of edge that meets a wall, back plus each end, to match a kit length.

Tiling or Paneling over the Flange

The question of how to tile over a flange has a short answer: the tile or wall panel runs down over the flange and onto the deck, and every joint is siliconed. On a walk-in tub that means the tub-to-wall line along all three sides, each corner, the line where the extension panel meets the tub, and the line where the end panel meets the wall. Existing wall tile that is sound and properly sealed can stay, and your installer confirms its condition. Keep the caulk line between the fixture and the wall in good condition afterward, and re-caulk if it ever cracks or pulls away.

Other Ella Parts Called a Flange

The word flange turns up on two other Ella parts, and naming the right one saves a round trip when you request a replacement.

• The swivel tray mounting flange. The tray's pin slides into a threaded fitting near the door, and its plastic mounting flange, like the tray itself, is a replaceable accessory. If yours cracked, What Are My Options If My Swivel Tray Broke or Does Not Fit? covers what to photograph.
• The flange of a control or fitting. When a hole is cut in the deck for a switch, push control or canister, the flange of that part sits over the edge of the hole and hides the fine surface lines a hole saw can leave, as Hairline Lines Around a Hole Cut in the Tub Deck explains.

Neither of those is a water barrier at the wall. When you ask about a shower flange or a tile flange, say so, and include your model and whether the base or tub is already installed so the right kit length ships.

Related Guides

• How Do You Install a Tile Flange on a Tub or Shower Base?
• Tile Flange, Caulking, and Finishing the Walls Around Your Walk-In Tub

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