A collapsible rubber dam, also called a water retainer, collapsible threshold or shower water stopper, is the self-adhesive flexible rubber strip that comes standard with Ella roll-in shower bases. It sits across the open edge of a barrier-free stall to keep water inside, yet it flattens under a wheelchair's wheels so the chair rolls right over it.

How It Works

The strip is a soft rubber profile with adhesive on its base. Standing, it forms a low lip that holds shower water on the base and directs it to the drain. When a wheel or a foot presses on it, it compresses and springs back afterward. Square end caps finish each end at the wall so water cannot slip around the corners.

Installation follows a 12-step sequence. The surface must be cleaned with isopropyl alcohol first, since the adhesive will not bond to soap film or dust. Start about 1/2 inch from the square corner, adhere the first few inches, then stretch the strip toward the center of the shower and press it down, working to the opposite corner. Cut the excess about 1/2 inch from the wall, dry-fit the caps, silicone them into place, and hold them with masking tape until the silicone cures. On tile, caulk the grout line beneath the retainer so water cannot travel under it.

Which Ella Models Have It

The collapsible rubber dam is a shower accessory, not a walk-in tub part. It ships standard with Ella roll-in and barrier-free shower bases. See shower base sizes and thresholds compared to see which bases are barrier-free, shower base and dam installation for the full sequence, and SMC shower base installation for the sheet molding compound bases.

What to Know as an Owner

Never drill into the threshold of a shower base to fasten the dam or anything else; drilling into a shower base threshold voids the base warranty, as described in shower base warranty coverage. The adhesive and silicone are the only fastening the dam needs.

Wipe the dam with a soft cloth and a mild cleaner, and check the end caps and the silicone at each wall now and then. If water is escaping, look first at the caps, the grout line under the strip and any spot where the adhesive was applied over a surface that was not cleaned with alcohol. If you contact support at ellasbubbles.com/support, have the base model, a photo of the dam and caps, and a note on where the water is getting out.

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