What Is a Shower Dam and When Do You Need One?

A shower dam is the flexible, collapsible rubber strip that runs across the open entry of a barrier-free roll-in shower to keep water inside the stall while a wheelchair or walker rolls right over it. You need one when your shower base has no curb to hold water back, which is exactly the case with Ella's roll-in bases, and that is why the dam ships as standard with them. The strip itself and its installation are described in What Is a Collapsible Rubber Dam on a Roll-In Shower?; this page covers when a dam is the right water control, when a molded threshold, screen or weighted curtain does the job instead, and how the options line up across Ella's bases.

Why a Curb-Less Shower Needs a Dam

Ella's wheelchair accessible roll-in base is a curb-less pan with no lip to cross, so a wheelchair or shower chair rolls straight in. The AcrylX barrier-free bases have a beveled roll-in entry of only 3/4 inch to 1 1/8 inch depending on size, and SMC bases are 1 inch or 1 1/8 inch. That is the lowest entry of any Ella product, and it is also too low to hold shower water back on its own. The collapsible rubber dam, also called a water retainer, flexible shower dam or collapsible threshold, solves that. It is a compressible, waterproof strip that sits across the open entry: the wheels flatten it while entering or exiting, and it returns to its original shape once they pass, so you can shower and keep the water in the stall. The video shows the dam being installed with silicone, then compressing under a wheel and springing back, and finishes with a demonstration of how well it contains water. In short, it gives a barrier-free shower the water control of a curb without the curb.

Which Ella Bases Come with a Dam and Which Do Not

The dam is made for exclusive use with a barrier-free wheelchair accessible base, and it ships as standard with Ella's roll-in bases. Bases with a molded threshold do not need one, because the raised edge does the same job. The printed threshold figures below come from Shower Base Sizes and Thresholds Compared.

The pattern is simple. If the entry is about an inch or less and someone is rolling into the stall, plan on the dam. If there is a 3, 4 or 5 inch edge, the bather steps over a threshold that holds the water, and no dam is involved. On the AcrylX package sheets the dam is listed alongside the other package options, and accessories ship loose for field installation, so your installer sets the dam after the base is in place.

Dam, Shower Screen or Weighted Curtain: Three Different Jobs

People searching for a shower dam often also ask what a shower screen or a weighted shower curtain is, and the three do different jobs. The dam controls water at floor level. The open side of an Ella shower, above the dam, is finished with a curtain rod, a glass door or a screen depending on the package, and none of the packages include a roof, dome or top panel, as Does Ella Offer a Dome, Ceiling Panel or Light for Its Showers? explains. For a roll-in shower used from a wheelchair, the barrier-free base package options include a weighted anti-bacterial nylon shower curtain, a stainless curtain rod, a slide bar with hand shower, a padded 32 by 21 inch seat with fold-down legs, and grab bars in 24, 36 and 42 inch lengths. The weighted curtain and the dam work as a pair: the dam keeps water on the floor from running out the entry, and the curtain keeps spray inside above it. A seat is optional too, with folding benches and seats rated from 300 to 600 pounds or a 36 by 60 base with a molded seat. Shower products are sold per item, so a complete roll-in shower is put together from the base in your size and drain position, a wall system sized to it, and the accessories you choose; Should I choose a walk-in tub or a roll-in shower? lays out the pieces.

How the Dam Goes in

The dam attaches with strong, water-resistant self-adhesive tape, so nothing is drilled, and it is installed in 12 steps. That matters for the warranty: never drill into the shower base threshold, because drilling the threshold voids the warranty, so plan any door track or dam mounting with your installer so nothing penetrates it. The one non-negotiable rule is surface preparation. The mounting surface must first be cleaned thoroughly with alcohol, or the adhesive will not bond; the written guide calls for isopropyl rubbing alcohol, and the video uses denatured alcohol.

1. Measure precisely, clean the surfaces and lay a tape line on the floor as a guide.
2. Mark and cut the dam to length, then insert the plastic end caps.
3. Peel back about 24 inches of the backing, start about 1/2 inch from the square corner and press on the first 4 inches.
4. Stretch and align the strip toward the center of the shower and on to the opposite wall, pulling the backing away as you go, then press along the entire length.
5. Cut the excess about 1/2 inch from the wall, dry-fit the end caps and silicone them at their male ends and on the wall side.
6. Clean again, run painter's tape down both sides, and lay a thin bead of silicone along the lower edge of the dam on both sides and over both end caps. Masking tape holds the caps until everything cures.

On tile floors the grout line beneath the retainer must be caulked so water cannot travel under it. Let the silicone cure fully before the first shower.

When You Do Not Need a Dam

Choose a walk-in tub rather than a roll-in shower when you want to sit and soak. Its sealed door and molded seat hold water without any dam, and you can still shower from the seat with the hand shower. Choose a low-threshold shower with a molded 3 inch, 4 inch or 5 inch edge when the bather can step over a small lip and no wheelchair is rolling into the stall. The dam is only for the curb-less roll-in base. Walk-In Tub or Low-Threshold Shower? compares the two on mobility, space and caregiver needs.

Once the dam is in, rinse it with the rest of the floor, use only the non-abrasive cleaners recommended for the base, and check periodically that the ends and caps are still sealed to the wall. If the dam ever lifts, the cause is almost always a surface that was not alcohol-cleaned or grout that was left uncaulked. For a ticket at ellasbubbles.com/support, have the base model and the date of installation ready, or ask your Ella dealer or the team at (800) 480-6850 about a replacement.

Watch: The Ella Shower Dam, Keep Water In, Roll In With Ease | Ella's Bubbles with chapters and a full transcript.

Related Guides

• Installing Ella Shower Bases, the Flexible Shower Dam, and Shower Walls
• What is a roll-in shower for wheelchair users?

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