What causes cracks in walk-in tub acrylic and how do I prevent them?

Cracks in a walk-in tub's acrylic surface are uncommon on an Ella tub, and when they do appear they are almost always fine stress marks in the finish around a hardware mounting point rather than a break through the shell. The most common spot is the finish around a grab bar, where pressure at the bolted mounting points can show up over time as fine cracks or whitening. Prevention comes down to how the shell is cleaned and what is bolted through it, and a mark that does appear can often be repaired in place, as explained in Cracks or Stress Marks in the Acrylic Finish: How a Local Refinisher Repair Is Arranged.

How the Shell Is Built, and Why It Resists Cracking

Every current Ella walk-in tub starts as a solid acrylic and ABS sheet that is heated and vacuum-formed over the mold into one seamless surface. The team describes the acrylic as roughly 1/8 to 3/16 inch thick. Behind it, gel-coated fiberglass is applied for strength, and further fiberglass layers bond the shell and the stainless steel frame into a single structure. The white runs all the way through the sheet, so there is no separate finish layer to wear through.

That construction is the reason cracking is rare. In the video on this page, an Ella dealer compares acrylic with a fiberglass gelcoat tub: acrylic is one solid piece of material, the same material used for football helmets, and if it ever dulls it can be buffed back out. A gelcoat tub is built the other way around, with a thin sprayed gel coat as the bathing surface and fiberglass resin built up behind it. That sprayed finish is brittle, and because a tub expands and contracts as hot and cold water moves through it, gel coat chips and cracks and then needs a full fiberglass repair, refinishing and polishing. The side-by-side comparison is in Gelcoat vs Acrylic Walk-In Tub: Which Material Holds Up Better?. An Ella tub has gel coat only on the side you never see.

Where Cracks Actually Show Up: Hardware Mounted Through the Shell

Interior grab bars on an Ella walk-in tub are installed at the factory and bolted through the acrylic shell, because a bar has to carry a bather's weight. The support team's experience is that pressure at those mounting points can show up over time as fine cracks or whitening in the finish, even on a bar that is rarely used. Because these marks are in the finish itself, an acrylic refinisher can usually repair them without the tub being replaced.

The same principle explains why the shell should never be drilled and a bar never modified. A replacement interior bar is matched to your tub's mounting hole spacing rather than chosen by size alone, and the deck-mount bar that ships loose in the parts box seals with rubber washers when your installer mounts it on the rim. What Is the Ella Grab Bar and How Is It Used? covers both kinds of bar and how each is fixed to the tub.

Crack, Scratch or Scuff? How to Tell Them Apart

Many marks reported as cracks turn out to be surface blemishes that polish out at home, so look closely before you worry.

• Light scratches and dull spots are on the surface only. They can often be restored to their original luster with a fine grade, automotive type cleaning and polishing compound, such as Turtle Wax brand products, worked in small circles with a soft cloth, then rinsed and dried.
• Stubborn marks, sticker glue and caulk residue come off with a mild detergent first, then denatured alcohol or Clorox Soft Scrub cleaner. They are not cracks.
• Fine lines or whitening that radiate from a bolt or fitting and do not change when polished are stress marks in the finish. Stop polishing and photograph them.
• Anything deeper than the gloss has a clear path through the support team. Ella's Bubbles does not sell a standalone touch-up kit, so do not wait for one.

The full home-care routine, including the approved cleaners, is in Scratches, Scuffs, or Discoloration on the Acrylic: Surface Care and Touch-Up Kits.

Prevention: What Protects the Finish

1. Clean with non-abrasive products only. Abrasive cleansers and scrubbing pads are the one thing that will permanently damage the gloss. Stick to the gentle products in the approved cleaners list.
2. Keep bleach out of the tub. Bleach can damage acrylic over time and is not part of the Ella's Bubbles cleaning instructions. For residue in the jet lines, use the published vinegar flush instead, as described in Black Flakes, Brown Slime, or Debris Coming From the Jets: Cleaning Steps That Work.
3. Do not drill the shell or add hardware. Factory bars are bolted through the shell with matched hole spacing, and the deck bar seals with rubber washers. A hole made anywhere else creates a new stress point the shell was not built around, so a bar that does not fit is a question for the support team, not a drill.
4. Report the first sign early. A small stress mark in the finish is exactly the kind of damage a refinisher repairs in place. Send photos while it is small rather than waiting to see whether it grows.

What to Do If You Find a Crack

1. Take clear photos: one close-up and one wider shot that shows where the damage sits on the tub.
2. Find your serial number on the label behind the magnetic access panel next to the door, and note your model.
3. Write a short description of when the marks appeared and whether anything is mounted at that spot, such as a grab bar.
4. Open a ticket at ellasbubbles.com/support or call (800) 480-6850.

The team reviews the photos before recommending a repair route. When a finish repair is the right route, the team looks for an acrylic refinishing company that serves your area, or works with one you already trust, sends that company the job details, and the refinisher contacts you directly to set an appointment. Ella's Bubbles does not send its own technicians, and the warranty covers parts only and does not cover labor, so ask the team to confirm the arrangement for your specific repair before anything is scheduled. If the refinisher finds additional cracks during the visit, report those to the team as well so they can be reviewed.

Watch: Acrylic Over Fiberglass: The Better Walk-In Tub Choice | Voted Safest/Best 2020 | Ella’s Bubbles with chapters and a full transcript.

Related Guides

• How Ella Tubs Are Built: Acrylic Shell, Fiberglass Reinforcement, and Stainless Frame
• What can void my Ella's Bubbles walk-in tub warranty?
• Does Drilling Holes for a Faucet or Grab Bars Void the Ella Warranty? Pre-Drilled Holes, Reinforced Walls and Choosing an Installer

Common Questions