During a bathroom remodeling project, installing a new preformed shower pan is a common task. And it might be easier than you think to learn how to install a shower pan, depending on your skill level. As is true of buying a bathtub, you'll need to find a shower pan that will fit your space and work with the existing drain line. For example, if you are taking out a tub that has the drain on the right side, buy a shower pan that also has a right side drain to avoid adjusting plumbing.
Also, if you are installing a shower as a replacement to a bathtub, keep in mind that the ideal drain size for a shower is 2-inch pipe while most tubs are plumbed with 1 1/2-inch drains. Unlike a bathtub, which can hold much more water, a shower can be susceptible to overflowing if plumbed with 1 1/2-inch pipe. So in this case, you will need to make some plumbing adjustments to increase the size of the drain. One option is to bring a new 2-inch line over from the toilet drain line or the main drain line. Once you have that sorted out, you can get on to installing your shower pan.
Equipment / Tools
- Measuring tape
- Shower pan and drain fitting kit
- Plumber's putty
- Thin plastic
- Mortar, water, bucket, and trowel
- Screws with large heads (optional)
Carefully measure the location for the new shower to get the correct size for the shower pan.
Prepare the Space
Clean out the space for the shower pan. The walls need to be clear down to the studs. And the floor needs to be as clean as possible, so you can level the pan.
Dry-Fit the Shower Pan
Set the shower pan into place to gauge any changes you might need to make to the drain. Take measurements from the walls, so you can line up the drain.
With the shower pan in position, check along its edge to make sure it is sitting level. Use shims and make reference marks on the studs to make it easy to level the pan when you put it back in. Also, put some cardboard in the shower pan, and walk around on it to see how stable the pan is.
Attach the Drain Fitting to the Shower Pan
Remove the pan, and install the shower drain fitting into the opening in the shower pan. Apply plumber's putty to the bottom of the flange on the drain fitting before installing it. Screw the drain fitting onto the pan, and make sure it is tight. In most cases, there is a large retaining nut that threads onto the tailpiece of the drain fitting that you tighten to secure the fitting. Make sure to install whichever gaskets or washers that are included with the drain kit.
Depending on which shower drain you get, the 2-inch drain line might be designed to be glued onto the shower pan drain fitting. However, in most installations, a compression-style drain is the easiest to install because you can set the shower pan over the drain and then tighten the drain tailpiece onto the drain pipe with a rubber washer and nut.
Recheck and Make Drain Adjustments
Make sure the drain and shower pan line up nice and straight. Make any alignment adjustments necessary, and remove the pan again.
Lay the Mortar Base
Set some thin plastic down on the subfloor before laying the bed of mortar. Mix a bag of mortar, and spread it over the area where the shower pan will sit. The mortar should be about 1 inch thick. Stay away from the edges by a few inches to make cleanup easier. The fins on the bottom of the shower pan will embed in the mortar, creating a very rigid shower floor that won't flex when you walk on it.
Set and Anchor the Pan
Set the shower pan onto the mortar, and level it carefully. Tighten the drain into place on the drain line.
Some shower pans come with screws and brackets to attach the pan to the wall studs. Otherwise, you can use screws with large heads (such as roofing nails) to attach the flanges on the shower pan to the wall studs. Let the shower pan sit overnight for the mortar to set up before stepping into it.
Check for Leaks
Test the drain by pouring water into the shower pan. If you have access to the space below the shower, observe it from beneath the floor to check for leaks.
Now, you are ready to install the wall surfaces, faucet valve, and showerhead. A good solution for shower walls is a surround kit.