How Do I Install an Ella Shower Base on a Wood Subfloor?

Ella shower bases are designed to install on either a concrete or a wooden subfloor, so a wood floor needs no special base. What matters on wood is that the subfloor is sound and flat and level within 1/8 inch, that the base is dry fitted and the drain set before it goes in for good, and that it is bedded on beads of 100 percent silicone adhesive rather than a mortar bed. What the Ella Acrylic Shower Base Is Made Of and How It Is Installed describes the base itself, and this page is the step-by-step for a wood floor. A local licensed plumber or contractor does the work, and Ella's technical support answers their questions along the way.

Preparing the Wood Subfloor

Start by checking that the subfloor is sound. Soft or water-stained wood should be repaired before anything else, because the base bears on the floor directly and cannot bridge a weak spot. Then check that the surface is flat and level within 1/8 inch. If it is not, float it with leveling compound and allow it to harden fully before the base is set. Correct dips with the leveling compound rather than a mud bed, because the acrylic base's high-density foam reinforcement is designed to bear on a hard, level surface, and a mortar bed defeats that design.

Check the framing pocket at the same time. The barrier-free roll-in gel coat manual calls for a pocket 1/4 inch larger than the shower, with the framing square, plumb and level, and the framing table in that manual gives width, drain offset and depth for each unit. Have your plumber locate the supply lines and the drain before the base is positioned, since the drain has to align with the base and, on an acrylic base, the drain position is molded in and cannot be moved afterward.

Dry Fit, Mark the Threshold and Set the Drain

1. Dry fit the base in the framing pocket and level it. On a multi-piece gel coat unit, dry assemble the whole shower in an open space first to confirm the panels, the drain location and the alignment before moving it to the bathroom.
2. Mark the front of the threshold on the floor so the base can go back exactly where it was leveled.
3. Pull the base back out and set the 2 inch drain body according to the drain manufacturer's instructions.
4. On a barrier-free roll-in gel coat unit, follow the manual's drain detail: a 6 inch drain core with a 10 x 10 x 1/2 inch recess.

Setting the Base for Good

Where your model has wood shims or a support leg under the back edge, they must make solid contact with the subfloor. On the low-threshold gel coat units the wood support wedges are mandatory, not optional. Lay beads of 100 percent silicone adhesive at least 1 inch tall on the floor so the base is supported and bonded once it is lowered. Then lower the base over the drain, check level again, and screw the flange to the studs.

• Gel coat low-threshold units are joined with silicone at every seam, fastened with 6d galvanized screws every 8 inches on center, and leak-tested before the wallboard goes on.
• Barrier-free roll-in gel coat units call for two installers. Never drag or drop a fiberglass unit, not even an inch, because stress cracks follow, and keep cardboard or a drop cloth on the floor and seat while you work.
• The back of a fiberglass unit is not waterproof, so store it where water drains off until it is installed.

The full gel coat procedure, including the framing table and the slot-and-pin wall system, is in Installing Multi-Piece Gel Coat Showers: Barrier-Free Roll-In (BF) and Low-Threshold (SH) Units.

What Differs by Base Type

The difference for a wood floor is mostly in what sits between the base and the subfloor. The acrylic base relies on its foam and the silicone beads, the roll-in gel coat unit relies on a recessed drain core and a snug framing pocket, and the low-threshold gel coat unit relies on its wedges. In every case the 1/8 inch flatness rule is the same, which is why the leveling compound step comes first regardless of the model you own.

After the Base Is in

With the base bonded and the flange screwed to the studs, install the wall panels and follow the install guide for your specific base model. On the three-piece stalls the existing walls do not have to come down to the studs, because the unit's own panels are the wet surface, as explained in How do you install a three-piece fiberglass shower unit?. Ella shower stalls ship without a door, so a curtain, sliding door or pivot door is added afterward, and Does the Ella Shower Stall Come With a Door, and What Size Door Fits the Opening? covers how to size one. Inspect every unit on delivery and report any damage within 48 hours of receipt, because a damaged unit must never be installed. If your installer has a question that the manual does not answer, the team at ellasbubbles.com/support or (800) 480-6850 can walk through it with them.

Related Guides

• What Is an Acrylic Shower Base and How Does It Compare?
• Does an Ella Shower Base Need a Mortar Bed to Keep Its Warranty?
• How Do You Install a Tile Flange on a Tub or Shower Base?

Common Questions