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Extension panels and filler kits: fitting your walk-in tub into a 60 inch alcove

Updated September 2026

▶Glossary8
  1. Watch: Extension Panels Explained
  2. Which Models Include an Extension Panel
  3. What Is in the Kit
  4. Fitting Tips from the Ella Standard
  5. Order of Work on Install Day
  6. Freestanding and Double-Exposed Installs
  7. Related Guides
  8. Common Questions

Walk-in tub extension panels, also called filler kits, are what let a 52 to 55 inch Ella tub fill a standard three-wall 60 inch alcove with a clean, finished look. Tubs shorter than 60 inches include one custom-size extension panel, with a few exceptions listed below, and 60 inch and longer tubs do not need one. The panel can be placed on the left or right side of the tub, can be trimmed for out-of-square alcoves, rests on adjustable stainless steel shelf brackets that are part of the tub frame, and doubles as a handy shelf for towels, shampoos, and soaps.

Watch: Extension Panels Explained

Video
Chapters in this video
  1. 0:00 What Are Extension Panels? Ella's Bubbles walk-in tubs use extension panels to create the best fit for your new tub in your home.
  2. 0:14 Trimming Panels For Fit Extension panels can be trimmed to ensure your tub fits seamlessly and beautifully, even if your alcove is out of square.
  3. 0:29 Panel Storage Space The extension panels provide a convenient place for towels, shampoos, soaps, and other bathing items.

As the video shows, the extension panels come with integrated stainless steel shelf support brackets that are fully adjustable and are an integrated part of the tub frame, giving the panel a robust and durable support system. If your alcove is out of square or an unusual size, the panel can be trimmed for a seamless fit. Watch: Ellas Bubbles: Extension Panels or "Filler Kits" For Alcove Installation with chapters and a full transcript.

Which Models Include an Extension Panel

ModelExtension panel
Standard, Zen, FlowIncluded (Standard: 7 inch panel; Flow kit includes panel for 60 inch alcoves)
Standard60, Zen60Not needed (already 60 inch)
Ultra7 inch panel plus reversible end panel included
Elite, Petite, Royal7 inch
Deluxe4 inch
UltimateNone (60 inch tub)
Capri8 inch
Monaco, LoungerAvailable
Big4One, Shak, Front Entry, MobileNo extension panel
Transfer26, Transfer30, Transfer328 inch
TransferXXL5 inch
Transfer60None listed (60 inch tub)
Two-seat models (Tub4Two, Companion, Escape, Big4Two)None (full-length tubs)

For the Petite, use the actual width of 27.5 inches from the current spec sheet when planning; the 27 inch figure printed in the older extension-kit table of the stainless-family manual is a misprint. Our alcove fit and extension panels article and the dimensions by model table help you check the whole alcove before ordering.

What Is in the Kit

Kit contents vary by door family. Your kit matches your tub, so use this to verify nothing is missing before install day.

  • Standard/Zen/Flow (Economy platform) kit: 2 L-shaped stainless brackets, 1 L-shaped plastic bracket, 2 pressure metal clips, and 4 nuts. Installation uses 3 brackets and a clamp panel, pre-drilling holes 3/8 inch oversize, 7 screws, and silicone.
  • Ultra kit: 2 L-shaped stainless brackets, 7 x 1" x 1/8" bolts, 7 x 1" x 1/4" bolts, 1 x 1" screw, 9 x 1/2" nuts, 7 x 3/8" nuts, 14 medium and 14 small washers, 1 plastic washer, and 1 plastic cap.
  • Outward-swing and Transfer kit: 2 L-shaped stainless brackets, 7 x 1" x 1/8" bolts, 2 x 1" x 1/4" bolts, 2 x 1/2" nuts, 7 x 3/8" nuts, 4 medium and 14 small washers.
Ella walk-in tub extension panel kit hardware with stainless steel brackets and mounting hardware laid out
Extension panel kit hardware: stainless brackets, bolts, nuts, and washers. Check the count against your family's list above.

Fitting Tips from the Ella Standard

Video
Chapters in this video
  1. 0:00 Ella Standard Walk-In Tub Overview The video introduces the Ella Standard walk-in tub, highlighting its size and design for average bathers.
  2. 0:27 Fitting Tub Into Alcove Tips are provided for fitting the tub into a 60-inch alcove, including trimming the apron or using the standard end piece.
  3. 0:49 Hydro Massage System Features The tub's 18-jet hydro massage system is described, including its intensity control dial and inline water heater.
  4. 1:14 Drainage And Adjustable Frame The oversized two-inch drain and adjustable frame with access points for door adjustments are showcased.

Watch: Ella's Bubbles: Installation Tips For The Ella Standard Walk-In Tub with chapters and a full transcript.

The Standard comes equipped with an end panel for the faucet side and a 7 inch extension panel on the other side that mounts easily for a snug fit in a 60 inch alcove. If you are having an issue fitting the tub into a 60 inch alcove with the extension panel, the video recommends trimming the corner piece off the main tub apron for a cleaner, tighter fit. You can also slide the tub into the alcove using the standard end piece and apron without the end panel. On the Flow, the side panel must be cut 3/8 inch for a flush wall fit, and it attaches with magnets on the frame that meet tabs inside the panel.

Order of Work on Install Day

  1. Set and level the tub first, with every leveling leg firmly on the floor. The panel is fitted last.
  2. Measure the gap between the tub and the wall at the top and bottom, since alcoves are rarely square, and mark the panel.
  3. Trim the panel to the wall with masking tape over the cut line to protect the finish.
  4. Adjust the shelf brackets on the frame so the panel sits level with the tub deck, then secure it with the kit hardware.
  5. Caulk the joint to the wall and deck with 100 percent silicone after the tile flange and wall finish are in place; see tile flange and wall finishing.

Freestanding and Double-Exposed Installs

Every Ella tub can also stand free against one or two walls. One reversible end panel is included to cover an exposed end of the shell, and a second end panel is available when both ends are exposed. Our article on freestanding and exposed-side installations covers the layouts that work.

Walk-In Tub Extension Panels for Seamless Installation
Chapters in this video
  1. 0:00 Extension Panel for Seamless Installation The video introduces the extension panel, also called a fill kit, which allows for custom cutting to fit various wall spaces.
  2. 0:35 Integrated Shelf Support Bracket The video shows the integrated shelf support brackets, which are adjustable and made of stainless steel.
  3. 0:52 Panel Support and Durability The video explains how the integrated support prevents issues like silicone cracking or panel failure, making it a durable component.

This video shows the fill kit being set after the tub and cut to whatever the walls are, so an out-of-square alcove still gets a seamless finish and a place for soaps and towels. Underneath, the adjustable stainless shelf-support brackets on the frame carry the panel, so the load never rests on the silicone joint. Watch: Walk-In Tub Extension Panels for Seamless Installation - Voted Best/Safest 2020 with chapters and a full transcript.

Common Questions

Can the extension panel be trimmed to fit out-of-square walls?
Yes, the extension panel, also called a fill kit, can be trimmed to fit out-of-square walls. You should set and level the tub first, then measure the gap between the tub and the wall at the top and bottom. Mark the panel and trim it to the wall, using masking tape over the cut line to protect the finish.
What holds the extension panel up?
Adjustable stainless steel shelf-support brackets on the tub frame carry the load of the extension panel, not the silicone joint. These integrated shelf support brackets are fully adjustable and are an integrated part of the tub frame, providing a robust and durable support system for the panel. The panel sits level with the tub deck when secured with the kit hardware.
Can the panel go on either end of the tub?
Yes, the extension panel can be placed on either the left or the right side of the tub. You should position it on whichever end faces the gap in your alcove to fill the space between the tub and the wall.
Does the extension panel add length to the tub?
No, the extension panel does not add length to the tub itself. Its purpose is to fill the space between the tub and the wall, creating a clean, finished look in a standard three-wall 60-inch alcove. The tub's own length and interior dimensions do not change, and end panels also do not add length.
Which tubs do not come with an extension panel?
Full-length tubs such as the Ultimate, Transfer60, Standard60, and Zen60 do not need an extension panel because they are already 60 inches or longer. Additionally, two-seat models like the Tub4Two, Companion, Escape, and Big4Two are full-length tubs and do not include one. The Big4One, Shak, Front Entry, and Mobile models also do not use an extension panel.
Can I get extension panels on both ends?
One extension panel is included with tubs under 60 inches to help them fit into a standard 60-inch alcove. If your alcove is much longer than 60 inches, you should contact the Ella's Bubbles team with your measurements before ordering. This will ensure the right approach can be confirmed for your specific model and installation.
What if my alcove is shorter than 60 inches?
If your alcove is shorter than 60 inches, you should compare the tub's actual length and width from its spec sheet with your alcove dimensions. The extension panel can be trimmed down by your installer to match a smaller gap, or it can be left off entirely if the tub already fills the space. For example, a 52-inch tub plus a trimmed panel can fit a 55-inch or 58-inch alcove.
Can I opt out of the extension panel?
Yes, you can opt out of receiving the extension panel. If you do not need it for your installation, you can decline it on your order. This helps to reduce packaging waste.
I need a replacement panel or bracket. Where do I get one?
To get a replacement extension panel or bracket, you should open a ticket with Ella's Bubbles Support. Be sure to include your tub's model, serial number, and a photo of the specific part you need. The team will use this information to match the correct replacement part for your tub.
I only need a 4 inch filler. Do you cut the extension panel down?
The L shaped acrylic extension panel can be cut down with a saw by your installer to match a smaller gap, so a 52 inch tub plus a trimmed panel fits a 55 or 58 inch alcove. It mounts at the faucet end or the far end, whichever side you push the tub away from, and it is only needed when the wall to wall opening is longer than the tub.
Do you have a tub that fits a 4 foot opening?
For a 48 inch opening the fits are the Mobile 26 by 45 with an outward door and the Flow 28 by 48 with an inward door. A 30 by 52 tub needs the wall opened up, and a Front Entry 32 by 40 would stick out. A 53 inch space takes a 52 inch tub, and a 54 by 36 inch space has several options; the Ultimate needs the full 60 inches, so a 59 inch space between tile and vanity will not take it.
I cannot figure out which extension kit bracket goes where. Any pointers?
The two L brackets with the small flat tabs mount upside down at the top left and right corners so the panel rests on the tabs, the plastic L bracket sits at the bottom held by the bent bracket and its screw, and a bead of silicone where the panel meets the tub keeps it in place. A bracket bent in transit can be straightened with channel locks, and the matching bracket from the other side can be borrowed if needed.
Can Ella's Bubbles tubs be installed as fully freestanding units with all four sides covered?
No, none of the Ella's Bubbles tub models have panels covering all four sides, so they are not truly freestanding units. Every tub is designed to sit against at least one wall, with an end panel, a second end panel, or an extension panel covering the exposed sides depending on your layout. Check the freestanding and exposed-side installations article to see which wall configurations work for your model.
What end panel and extension kit come with the Triple XL 36 by 55 inch tub?
The Triple XL 36 by 55 inch tub comes with one reversible end panel and one 5 inch extension kit. Together they let the tub fill a 36 by 60 inch space. A second end panel is available through your Ella dealer or the team at (800) 480-6850.
Does Ella's Bubbles offer a panel for the back wall side of the tub?
Ella's Bubbles does not make a panel for the back wall side of the tub. Installers typically build a short wall there, or you can use an aftermarket acrylic panel from a big box home improvement store such as Menards or Home Depot. Your installer can help you choose the best finish for your layout.
Can an extra end panel hide the plumbing and mechanisms on an exposed end?
Yes, an extra end panel can cover the plumbing and mechanisms on an end of the tub that is not against a wall. Your tub includes one reversible end panel, and extra end panels are available through your Ella dealer or the team at (800) 480-6850.
How many extension panels and side panels come with the tub?
The tub comes with one extension panel and one side panel. If you need more coverage for an exposed side, an additional end panel can be added. Check the freestanding and exposed-side installations article to see which layouts work for your model.

Still need help? Open a ticket at ellasbubbles.com/support or call (800) 480-6850.

About this guide. Answers in the Ella’s Bubbles Support Center are compiled from real conversations with tub owners, our technicians’ notes and the product documentation, then reviewed by our team. Tub models and options have evolved over the years, so a detail here may differ slightly from your exact tub. If something looks different on yours, send us your serial number and a specialist will confirm it for your model.

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