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What Is a Shower Pan and What Does It Do?

Updated September 2026

▶Glossary6
  1. What the Pan Does
  2. Sizes, Thresholds and Drain Positions
  3. Checking the Pan Before Installation
  4. Related Guides
  5. Related Videos
  6. Common Questions

A shower pan, also called a shower base, is the molded floor of a shower: the piece you stand on, with the slope toward the drain, the threshold at the entry and the drain opening built into it. Ella pans are acrylic and arrive as the finished walking surface, so nothing is laid over them; the wall panels or tile come down over the edge of the pan so water runs onto the pan and to the drain rather than behind it. That is why the surface is left exactly as shipped, as explained in Can You Tile Over an Ella Acrylic Shower Base?.

What the Pan Does

  • Collects and drains water. The molded slope moves water to the drain opening. Your plumber connects that drain to the house waste line.
  • Sets the step-in. The threshold along the entry edge sets how far you step over to get in. Ella offers low-threshold and barrier-free versions as well as standard bases.
  • Seals to the walls. The pan meets the walls along its edges, and the wall finish comes down over that edge so water lands on the pan. This is the same principle as the tile flange on a walk-in tub.
  • Carries the load from below. The acrylic shell is supported from underneath during installation, which is what makes the floor feel solid. Adding tile, thinset or a membrane on top would bury the slope and threshold and trap water with no path to the drain.

Sizes, Thresholds and Drain Positions

Ella's pan lineup includes wheelchair roll-in models in 30x60, 32x60 and 36x60 inch sizes with left- or right-side configurations, seamless no-step-over bases in left- or right-side layouts, and custom acrylic bases made to fit a specific opening. Threshold height is the figure to check for accessibility projects. The Accessible Caregiver Shower Base is listed with a 3/4-inch threshold, while ADA standards generally limit a roll-in compartment to 1/2 inch, so commercial and public projects normally use the barrier-free line instead, as explained in Is a 3/4-Inch Shower Base Threshold ADA Compliant for a Commercial Building?. Ella does not offer a floor insert or riser to lower the drop on a stepped base, so the answer in that case is a different pan.

Every pan is also offered in more than one drain position, and each position has its own rough-in. The Specification drawing for your exact model and drain position shows the distance from the back wall and the side wall to the center of the drain. As two examples, one right-drain base lists the drain center 15 1/2 inches from the back wall and 9 1/2 inches from the front, while one center-drain base places it 19 inches from the back wall and 24 inches from the side wall. Have your plumber compare those figures with your existing drain line before you order; the method is in Shower Drain Rough-In: How Far the Drain Sits From the Back Wall and Side Wall.

Checking the Pan Before Installation

The installation video on this page shows the pan being dry assembled with its wall panels in a clean, open space before anything moves into the bathroom. That step confirms you received the correct panels and the correct drain location, that the pan and panels are free from damage, and that everything aligns. Photograph the assembled unit, and delay demolition of the existing tub area until you are confident the new unit is the right size and condition. The framing pocket is then checked against the framing diagram in the installation manual for size, square, plumb and level. When a wall is not plumb, the video shows the fix of shimming the pan away from the wall or notching the stud, because a pan that is out of plumb affects the wall panels above it. Refer to the installation manual for your model, and have a licensed plumber make the drain connection.

Chapters in this video
  1. 0:00 Introduction to Low-Threshold Shower Installation This video provides visual guidance for installing a low-threshold 3-piece shower, emphasizing the importance of referring to the installation manual.
  2. 0:24 Dry Assembly and Pre-Installation Checks The installer dry assembles the modular shower to ensure correct panels, drain location, and proper alignment before moving it into the bathroom space.
  3. 1:54 Preparing the Framing Pocket and Subfloor The installer checks the framing pocket for proper sizing, square, plumb, and level, making necessary adjustments and inspecting the subfloor for integrity.
  4. 4:07 Installing the Drain Body and Base Support The installer installs the drain body, prepares the drain to meet local plumbing codes, and applies silicone adhesive for proper support and adhesion of the base.
  5. 5:53 Permanently Installing and Securing the Base The installer permanently positions and levels the shower base, securing it to all available studs and cutting the drain pipe even with the rubber gasket.
  6. 7:22 Installing the Wall Panels and Valve The installer installs the wall panels using a pin and slot system, then installs the valve, connecting the hot and cold water supply lines.
  7. 10:19 Finishing Touches and Accessories The installer caulks all seams, recommends client involvement for accessory placement, and suggests an optional flange trim molding kit for a seamless transition.

Watch: Step-by-Step Low-Threshold Shower Installation for Remodeling | Ellau2019s Bubbles with chapters and a full transcript.

Chapters in this video
  1. 0:00 Receiving and Inspecting Your Shower This chapter explains how to receive and inspect your shower unit upon arrival, including what to do if there is damage.
  2. 1:17 Dry Assembling Your Shower This chapter demonstrates how to dry assemble your modular shower to ensure all panels and the drain are correct and undamaged.
  3. 2:49 Preparing the Framing Pocket This chapter shows how to check and adjust the framing pocket for proper sizing, squareness, plumb, and level.
  4. 5:02 Installing the Drain Body This chapter guides you through installing the drain body and preparing the drain to meet local plumbing codes.
  5. 5:44 Permanently Installing the Base This chapter details how to permanently install the shower base, ensuring it is level and properly supported.
  6. 8:12 Installing the Wall Panels This chapter demonstrates installing the wall panels using the pin and slot system, starting with the wall opposite the valve.
  7. 9:13 Installing the Valve and Wall This chapter shows how to install the valve and then the valve wall panel, including connecting the water supply lines.
  8. 11:13 Finishing and Sealing the Shower This chapter covers installing surface mount accessories, caulking all seams, and the option of adding a flange trim molding kit.

Common Questions

Is a shower pan the same thing as a shower base?
Yes. Ella uses both terms for the molded acrylic floor of the shower, the piece with the slope, threshold and drain opening built in. The Specification drawing and installation manual refer to it as the base or the pan.
Can I tile over an Ella shower pan?
No. The pan is a finished acrylic surface, and tile will not bond properly to acrylic. Tiling over it would cover the molded slope and threshold and could trap water underneath. Plan a tiled look for the walls above the pan instead.
Where does the drain sit in the shower pan?
It depends on the model and the drain position you order. The Specification drawing shows the distance from the back wall and the side wall to the center of the drain. Always state left, right or center when you ask for a measurement.
What is the threshold on a shower pan?
The threshold is the raised edge along the entry side that you step over. Its height varies by base type, from the 3/4-inch caregiver base to barrier-free bases designed for curbless entry. Check the figure on the spec sheet rather than judging from a photo.
Is the Accessible Caregiver base ADA compliant for commercial work?
Its 3/4-inch threshold sits above the 1/2 inch figure ADA standards generally apply to roll-in compartments, so it is normally not the right choice for that requirement. Ella offers barrier-free bases and custom sizes for those projects. Confirm every requirement with your local building department.
What should I check about the pan when the shower arrives?
Dry assemble the pan with the panels in an open space to confirm the correct size, the correct drain location and that nothing is damaged. Photograph the assembled unit. Do not demolish the existing tub area until you are confident the unit is correct.

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