Categories Commercial Plumbing, Residential Plumbing

Shower pan leak 101

What is a shower pan?

A shower pan is a rubber membrane installed under the sloping floor and tile of your shower.  If installed correctly, you will most likely never need to replace it.  Florida plumbing code states there must be a shower pan installed on any second floor or higher shower.  You are not required to install a shower pan on first floor showers if the shower base and drain are depressed or sunken a minimum of two inches below the finished living area floor

This old pan had a poured curb or flood rim, some build the curb with 2×4’s and wrap the pan material around it. This pan did not extend up high enough at the sides.

Why is my shower pan leaking?

A shower pan can leak for a variety of reasons, the most common would be incorrect installation. After a shower pan is installed, it is very important to carefully work around it as to not damage it. A simple screw stuck to the bottom of a workers shoe could puncture a shower pan. The shower pan should be installed a minimum of  one inch above the showers curb or flood rim. All screws attaching the the pan should be fastened above the flood rim. In the picture below, you can clearly see the pan does not extend above the flood rim and screws were used to fasten the liner below the flood rim. Corners of the shower pan should be neatly folded and not cut. We have seen many pans cut at the corners, then glued back together to form a neat corner.

This shower pan does not extend above the flood rim and has screws installed under the flood rim

If the pan was installed wrong, why did it take years to leak?

The shower pan is a last defense from leaking. A new shower with new grout may not let water get to the concrete or pan. Tile companies and general contractors use an un- sanded grout in showers, it is waterproof until it cracks or wears out. If you see cracks forming in your grout lines, caulk or re-grout them.

How do we test a shower pan?

We first start by drying the area and ask our customers not to use the shower.  If visible moisture and water continue to appear, a hot or cold pressure line to the shower or other fixture is leaking. We then remove the shower head and install a cap. The riser to the shower head is then pressurized. This riser line to the shower head would only leak when the shower is on and running so it is important to test this line before assuming the pan is bad.  Then we istall a test ball to block off the drain to the shower, fill the shower base up to the flood rim and take a measurement of how much water is in the base of the shower.  After 1/2 hour, we take that same measurement at the exact same location and record any water loss. If the water has dropped anymore than 1/4 inch, the pan has failed. In most cases you will visibly see water coming out of the shower area or water dripping down from a second floor, in this case the measurement is not necessary.

Installation and pre-slope  

We highly recommend installing a shower pan in every shower, minimum plumbing code is exactly that, minimum.  Pre- sloaping is something we don’t often see, the ground area below the installed pan should also be sloped toward the drain. If you have ever stepped into a shower and felt the base move or feel spongy, it’s because there is no pre slope and the concrete and tile above the pan are floating on the pan. Eventually the water in your shower will make it past the tile, concrete and grout. If the shower was pre sloaped the pan will catch this water and direct it to the weep holes of your shower flange.  We also recommend replacing the shower flange when replacing the pan, we use a silicone sealent to the bottom side of the flange but not the top, the topside is where the water will enter the weep holes, carefull not to clog these channels or holes.

Here you can see the old pan, flange were removed, it is ready for pre-sloping, new flange and rubber pan.