Building A Ceramic Tile Shower

The most important part of a custom built shower is the receptor, or shower pan.

A major project like a custom shower needs advance planning.

If you are planning a custom built shower for your home building or remodeling project, here are a few things you should know about the process while you are in the planning stages.

You can build any size shower you like, which is one of the benefits of building a shower from the base up; in other words, not using a commercially available shower pan of the drop in type. What you are going to do is build a shower pan with mortar and tile, and a waterproof membrane to form the pan.

The correct installation of the vinyl pan liner

After you have determined the size of the shower, your contractor will frame the walls, which may be full height all around, with one side open for the entrance, or there may be "knee" walls, the remainder to be enclosed with glass.  The contractor will have his plumber install a special shower drain, which has a sub drain through which water will be carried away from the plastic liner beneath the surface of the floor through weep holes.  Here is where a major problem arises in construction method depending on who does the work from here on, and this needs to be carefully considered before any work proceeds, because there will in turn be a large difference in the cost factor of the installation, and a potential health risk if it is done incorrectly.

It has been our experience that if a plumber installs the vinyl pan liner, and many do, he will typically lay the liner flat on the subfloor.  The liner will extend up the walls a given height, and will be clamped at the drain with the clamping ring that comes with the drain.  The tile contactor will then fill the floor with "deck mud" (a rather dry mix of sand and cement), and slope the surface to the top of the drain, leaving enough room for the thickness of the tile at the drain.

The problem with this method, and why it is not good practice, even if a general contractor will allow it (though it is in violation of the Uniform Plumbing Code), is that without a pre-slope under the shower pan liner (1/4" per foot minimum) to the sub surface weep holes, the liner cannot drain the water effectively. Water will accumulate underneath the floor, the floor will become waterlogged, and a serious mold and mildew problem will be the result.

The pan liner must always be sloped to the sub drain to allow water to drain off.  Further, it is a requirement of the Uniform Plumbing Code.  If a tile contractor, or plumber tells you that it is not necessary to pre-slope the vinyl liner, get another contractor.  It is your home. Insist that it be done correctly.

If we are doing your installation, we will insist on installing the pan liner ourselves, so that it is properly sloped to the sub drain.  This means building a sloped surface with deck mud prior to installing the liner, and then laying the liner on this pre-sloped mud bed. After the liner is installed, and properly fastened up the walls, the finished floor upon which  the tile will be set,  approximately 1-1/4" to 2" thick,  is "floated" with more deck mud.

It is important to note also that there can be no fasteners put through the liner anywhere inside the shower except at the very  top, which should be 3" above the top of the curb.  The liner must be folded at the corners, must wrap over the curb, and may only be fastened to the curb on the outside face. In addition, corners must be installed and sealed at each side of the opening where the liner must be cut to wrap over the curb. This is an area where a large potential for leaks exists if not done correctly.

Since the widest vinyl liner available is 6' wide, and since a good amount of this must wrap up the wall of the shower, the shower size is limited, unless this liner is seamed.  Seaming the liner will ad to the cost of the installation.

Framing requirements for the pan liner

Before the installation of the pan liner, the contractor must place blocking between the studs around the entire perimeter of the shower to support the vinyl liner around the walls.  The blocking must extend up as high as the top of the liner, as the liner will be fastened at the top to this blocking all around the walls.  This blocking is often omitted by the building contractor.  We will insist upon it, or we will install it ourselves. The height of the curb will be determined by the size of the shower, taking into consideration a min. 1/4"/foot slope  of the floor to the drain.  The dam height inside the shower should be at least 2", unless the shower is large enough that a dam will not be required (rarely the case in residential showers).

Any knee walls must be absolutely plumb and square, and must be installed in such a way that they are sturdy, with no movement. If a corner bench is to be installed, this must also be taken into consideration in the framing, with blocking provided. Also, if glass is to be placed on top of the knee walls, the vinyl liner must extend up and over the top of the knee wall, otherwise water will get into the wall and leak out at the floor.


A bench seat can be added to a large shower, either a corner bench or a bench the width of the shower. A bench built out of wood framing by the contractor will require additional waterproofing, which will necessarily ad a significant amount to the cost of the job, as these waterproofing materials are expensive.  Alternatively, a prefabricated bench which needs no waterproofing and can be tiled on directly, may be used. They are available in two corner sizes, and an adjustable size for a full width bench.  They offer plenty of support (rated up to 400 lbs), and may even be added after the tile is installed, but we install them after the installation of the cement backer board.

What it costs

The more complex the design, the greater will be the cost.  A custom shower cannot be priced simply on a "per square foot" basis, and any installer who wants to give you a price simply based on the square footage (believe me, we have run into this), probably doesn't know what is involved. You would be wise to show him the door.  I have personally torn out an uncompleted shower which  the installer had priced so low as to be ridiculous. I had to start all over again from scratch, when  the homeowner realized that the installer had no idea of what he was doing.

There are too many variables to be considered, such as knee walls, corner entry (requiring a 45 degree curb), bench, and other options and design factors, waterproofing requirements, and installation of accessories such as shelves, niches, and even decorative accents.  Every option including the type of tile and trim, must be considered when working up a cost estimate.  Some tile and trim can be more difficult to install, and is therefore more labor intensive.  In some tile lines, all the necessary trim pieces may not be available which requires other trim options.  This, too, will necessarily increase the cost. Therefore, it is important to find this out in advance. All these things must be kept in mind from the early planning stages, or you may quickly exceed your budget.