Installing a Shower Pan Membrane Liner for a Custom Ceramic Tile Shower

Tips on How to Install a Shower Pan Membrane Liner

By Mark J. Donovan

One feature to seriously consider when planning a bathroom remodeling project is the inclusion of a custom ceramic tile shower. Nothing beats the elegance and charm of a custom ceramic tiled shower. And surprisingly, they are not as expensive to install as you may think, particularly if you are willing to put some sweat equity into it.

Most moderately skilled DIY homeowners can install their own ceramic tile shower with a little upfront education and planning. The only really critical component of a ceramic tile shower is the proper installation of a shower pan membrane liner.

A shower pan membrane liner is the item that ensures any water that may seep through the ceramic tile shower floor gets funneled into the shower drain.

If installed improperly the shower could leak and you’ll end up having to rip out tile and make time consuming and messy repairs. The improper installation of a shower pan membrane liner on a second floor shower can cause even more damage. So you want to make sure you get this part of the project right the first time.

A shower pan membrane liner is made from flexible plastic material. It is sandwiched in-between two layers of mortar on the shower floor area. The ceramic shower floor tiles are attached to the top layer of the mortar. The mortar has a gentle slope to it so that the shower pan membrane liner can funnel water into the shower drain.

To install a mortar shower pan membrane liner the first step is to install a pre-slope layer of mortar to the subfloor, be it plywood or a concrete slab. This pre-slope layer is designed to provide a gentle slope from the shower wall edges to the shower drain. After pouring mortar onto the plywood subfloor or concrete slab, it is troweled to create the proper pitch to the shower drain.

How to Install a Mortar Shower Pan Membrane Liner eBook.

After the pre-slope mortar layer has setup the flexible shower pan membrane liner is placed on top of it.

The shower pan membrane liner needs to be properly folded into the corners and tacked in place to the wall studs using roofing nails. The nails that hold it in place should be around 6 inches up from the bottom of the shower pan. In addition, a hole has to be cut in the shower pan to allow the adjustable shower drain to pop up through.

Cement backerboard can then be attached to the shower frame wall studs. Cement backerboard is a cementitious material that is ideal for fastening ceramic tiles to. It is also impervious to water. Do not use drywall or moisture resistant drywall in a ceramic tile shower project. Also, it is critical not to damage the shower pan membrane line while installing the cement backerboard. Make sure to put cardboard over the membrane liner when installing the cement backerboard.

With the shower pan membrane liner and backerboard installed, a final base layer of mortar is poured into the shower pan area to cover the membrane liner.

Again, the gentle slope needs to be maintained with the second mortar layer such that water drains from the shower wall edges to the shower drain. Use your trowel to do this.

After the final base layer of mortar has fully cured, you can then move onto the process of tiling the shower walls and floor. Note that you should use an alkaline resistant tape and thinset mortar to cover the seams in the cement backerboard prior to tiling the walls.

Lastly, after grouting the ceramic tile shower walls and floor, adjust the shower drain assembly so that it is flush with the finished shower floor surface.

For information on installing a shower pan membrane liner for a ceramic tile shower, see the Shower Pan Membrane Liner Installation Ebook from  The Shower Pan Membrane Liner EBook will quickly teach you the step-by-step process for installing the shower pan membrane liner correctly. It includes instructions on framing the shower stall, pouring the pre-slope and shower base mortar, and installing the shower pan membrane liner.

See’s Ceramic Tile Calculator

See my “How to Tile a Custom Ceramic Tile Shower” Ebook to learn how to tile your own shower:  For a detailed set of instructions on tiling a shower floor and walls, including pictures for every step in the process, see my “How to Tile Custom Ceramic Tile Shower Ebook”.

Related Information

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