How do I measure for a new shower pan or base?

To measure for a new shower pan or base, take three sets of numbers: the alcove width and depth measured at the studs, the position of the existing drain measured to its center from the back wall and the nearer side wall, and the threshold height you want. Compare them with the specification drawing for the base you are considering, because every Ella base has a fixed size and a molded-in drain position that cannot be trimmed or moved on site. Ella Shower Rough Opening, Standing Area and Floor Width: What to Measure Before You Frame explains how to read that drawing.

Step 1: Measure the Opening at the Framing

The base sits against the framing once finish materials are removed, so measure the alcove width between the studs and its depth from the back studs to the front. The nominal size in a base's name describes the alcove it is built for, and the drawing gives the exact opening to frame. If your alcove is wider than the unit, the extra space is furred out before installation. Check that the floor is flat and level while you are at it. An Ella base sets directly on a sound subfloor or a concrete floor, never in a mortar or mud bed, and dips are corrected with self-leveling compound.

Step 2: Locate the Drain

Have your plumber measure from the center of the existing drain pipe to the wall framing behind it and to the framing on the nearer side wall. Every Ella base drawing gives the drain location the same way, as the distance from the back wall and the side wall to the center of the drain opening, and those figures change with the model and with a left, right or center drain position. As two examples from the drawings, 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. If your numbers match the drawing within the tolerance your plumber is comfortable with, the base can be set over the existing line. If not, a licensed plumber can relocate the drain, or you can ask about a custom base with the drain placed to suit your line. The comparison method is in Shower Drain Rough-In: How Far the Drain Sits From the Back Wall and Side Wall.

Step 3: Choose the Size and Threshold

Standard sizes such as 60 by 30 and 60 by 33 inches are stocked, and other sizes are made to order. The base has to be sized before it ships, because cutting into the molded acrylic shell and its high-density foam reinforcement is not possible on site. How the base is built and set is covered in What the Ella Acrylic Shower Base Is Made Of and How It Is Installed. Custom bases run from a minimum of 30 by 30 inches up to 80 inches long by 44 inches wide, with the threshold on the longer side; corner bases go up to 42 by 60 inches. Custom builds are low step-in pans, pictured with 4 inch and 2 inch thresholds, and a true roll-in threshold needs different molds, so ask before you plan on one. Confirm the program is open for your size with your Ella dealer or the team at (800) 480-6850, as described in Custom-Size Shower Bases: Size Ranges, Threshold Options, Drain Placement Rules, Construction, and How to Request One.

Step 4: Dry Fit Before You Plumb

Treat the drawing as the starting point and the dry fit as the final word, because framing variations and wall thickness can shift the base slightly. Set the base in the pocket, mark the drain center through the base opening, and only then cut and set the drain pipe. Remember that the acrylic base is the finished floor. It is not made to be tiled over, so plan any tile for the walls above it, with the wall finish coming down over the base edge.

Related Guides

• Shower Base Sizes and Thresholds Compared: AcrylX Barrier-Free, SMC Linear-Drain, Molded-Seat and Cultured Marble Bases
• How Close to the Wall Can the Drain Be on a Custom Shower Base, and Can It Be Centered?
• Ella Shower Dimensions: Nominal Size Versus Usable Interior Floor

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