How to Tile a Premade Plastic Shower Pan

Modern bathroom shower

 

dimarik / Getty Images 

When you are considering remodeling your bathroom, usually one thing to be replaced is often the shower, bathtub, or shower/bath combination. That's usually an easy decision. But from that point, it gets harder. Do you install a pre-fabricated shower stall or a tiled shower?

Instead of choosing between one or the other, it's possible to have a combination: tile the walls and still install a synthetic shower pan. This gives you the beauty of the tiled walls and the easy installation of a prefabricated pan.

For tile purists, the only issue with this approach is that you have a synthetic shower pan that looks synthetic. The beauty of the tile ends at foot-level.

Now you can get the best of both worlds. With the right type of shower pan, you can have an easy-to-install, virtually leakproof prefabricated synthetic shower pan and tile. For do-it-yourselfers, this is much easier and far more foolproof than the traditional tilers' method of forming a shower base from scratch.

Pros
  • Pre-sloped: no need to slope and incline the tile

  • Possibility of leaking greatly reduced

Cons
  • Several times more expensive than building a mortar-base tiled shower pan

  • About twice the cost of a conventional (non-tile) synthetic shower pan

Tile-Over Shower Pan Basics

Often called tile-over shower pans, shower pans that are designed to accept tile are heavier and sturdier than a normal pan so that they can withstand the weight of most users without cracking the grout or tile.

In a typical installation, the shower pan is set into a bed of mortar to level it and to secure it to the subfloor.

Next, the walls are covered with cement board and are sealed to the pan with silicone caulk or with a special flashing followed by caulk.

The tiles adhere to the base either with conventional modified thinset or with an epoxy adhesive supplied by the shower pan manufacturer.

You cannot tile over standard polymer or fiberglass shower pans because they flex too much and will eventually crack the tile grout and possibly even the tile itself.

Tip

It's helpful to dry-fit and pre-cut all of the tiles before applying the tile adhesive or thinset. Since the shower pan is already at its eventual size, there will be no size changes along the way. You can even dry-fit these tiles outside of the bathroom itself if there are any space limitations.

Tile-Over Shower Pan Installation

The standard installation of a tile-over polyurethane shower pan starts with a framed-in shower alcove that is sized for the shower pan. If the subfloor is wood, it should receive a layer of cement board to protect the wood from the mortar bed under the pan.

If there is access to the drain connection below the shower, the subfloor simply needs a hole for the shower pan drain assembly to fit through. The final drain hookup can be made after the shower is completed.

  1. If there is no access below, the drain must be stubbed out to the proper height below the subfloor surface, and the shower pan drain assembly must be glued to the stubout when the pan is installed.
  2. Frame the shower or shower/bathtub stall to the dimensions that come with the shower pan. Start by purchasing the shower pan (or referring to instructions) before framing out the enclosure.
  3. Dry-fit the pan's drain with the subfloor's drain hole.
  4. Fit the shower pan itself into the shower or tub framed enclosure to check for proper fit.
  5. Prepare the PVC or ABS drainpipe. It should extend upward far enough that it fits the target drain hole of the shower pan and it should be flush with the shower pan floor.
  6. Remove the shower pan.
  7. Apply the waterproofing to the subfloor. Waterproofing methods include: liquid membrane, tar paper, or a synthetic solid membrane.
  8. Mix up the mortar for the base of the shower pan.
  9. With a trowel, spread the mortar across the subfoor to the depth specified by the shower pan manufacturer. The mortar should be spread evenly across the subfloor. Otherwise, pockets will develop in the mortar that will create hollowness below the shower pan.
  10. Carefully lay the shower pan on top of the mortar base. Apply enough pressure across the entire shower pan to evenly set the pan into the mortar.
  11. After the shower pan mortar is solid enough to walk on, install the cement backer board on the walls of the shower. Seal all joints with silicone caulk.
  12. Tile the floor and the sides of the shower pan with modified thinset. Use a notched trowel to regulate the flow of thinset across the shower base.
  13. After the thinset has cured solid, grout the tile.