A shower pan liner is a pan-shaped waterproof barrier placed under the floor of a shower.
Its purpose is to catch any water that seeps through the tile and groutThen, it directs the water to the drainThe liner, therefore, keeps the floor from water damage, fungus, and mold.
- Acquire a permit
In some environments, plumbing projects require a permit to be carried out. It is advisable to comply with the law and acquire the permits. In such cases, the permit works as an insurance policy. It covers the owner of the building from crooked contractors. Once your local building inspector approves the installation project, the work kicks off.
- Prepare the location of the pan liner
For a shower sitting on a concrete floor, take away the concrete material between the old drain location and the new one. Afterward, remove the old trap and add a new section of a drain pipe. Then install the trap and the shower floor drain assembly at the chosen location. The work leaves behind a hole in the slab that needs fixing. If not so, it may cause grout cracks in the future.
To repair the slab, backfill the hole with the debris and sand from the relocation process. This helps to save the construction materials. The backfilling material should be below the bottom surface of the slab.
Secondly, make a batch of mortar to fill in the slab’s hole. Make a quality mortar by following the manufacturer’s recommended ratio. Finally, pour the mortar into the hole and using a trowel, shave the surface. Before the mortar dries, clean up the surface.
If the bathroom lies on a wood subfloor, you need to cut a new opening which is of the same size and shape as the original one. Use the cutout to fill the left opening after doing away with the plumbing work.
- Come up with the pre-slope
In the more traditional tiled shower floors, you have to create a slope. It allows all the moisture to drain thus keeping off a bad odor, fungus, and mold. According to the Tile Council of America & ANSI standards, use “slope under waterproofing membrane”. The plumbing codes also require a slope of ¼ inch per foot.
As the installer, you can create the slope in three different ways. First, you can pitch the floor framing to form the slope. You can also use a special product from manufactures that generate the required slope for you. Lastly, you can come up with a slope by laying a bed of latex-modified mortar onto the surface.
- Install the drain fitting flange
A flange, clamp ring, and drain barrel opening make up the shower floor drain. The function of the flange is to mount to the sewer pipe. The clamp ring on the other hand holds the pan liner in place. The drain barrel keeps the completed drain grate at the right height.
To fix the drain base in place, disassemble the drain fitting and then set aside the flange and the cap. Install back the flange bolts and using the subfloor, cut the sewer pipe. To the sewer pipe and drain flange, apply PVC cement. Finally, lay the drain flange in the opening.
- Buy the shower pan liner
To purchase the appropriate shower floor membrane, you should be aware of the shower floor’s dimensions. Measure the length and the width and round off to the nearest foot. Also, add at most 1 foot per wall to your measurement to be on the safe side.
- Create a long-lasting waterproof seam
In cases where the shower is large, you need more than one section of the pan liner to cover the wall overlap and the floor. This is achievable by using a specialized cement that is specifically designed for pan liner. This helps to glue together the membrane sections. Before you continue with the installation, break for 15 minutes.
- Install the pan liner on the drain flange
Kick-off by placing the liner on the shower floor at the center of the stall. To expose the drain flange, fold the pan liner into half. Be careful to drift the position of the shower membrane from the stall’s center. Apply silicone caulking 3/8inch wide on the outside perimeter of the drain flange. It provides a seal between the drain base surface and the liner underside. Unfold the pan liner and press it down with fingers to bring out the drain flange’s bolts.
Press the shower pan liner against the silicone and remove any creases. To install the locking ring, place over the bolt heads on the bigger part of the locking ring’s keyhole-shaped openings. Finally, clear the drain opening by taking away the pan liner from the locking ring’s hole in the center using a utility knife.
- Join the pan liner to the curb and the walls
From the wall center, work towards each wall stud. Where the wall meets the floor, make a tight fold in the pan liner using one hand. Position the membrane against the wall stud using the other hand. Join the pan liner to the wall stud using stainless steel screws and keep them at least ½ inch below the pan liner’s top.
To join the pan liner with the curb, cut the membrane carefully from the top of the curb up the wall. Ensure the shower pan liner material overlaps the curb and the seal the cuts using corner guards.
- Test the shower pan liner
To make your installation sure, close the drain opening using a test plug. Using water, fill the pan up to the top of the curb and let it sit for four hours. Check for any leak and repair if any. Mainly leaks are caused by poor liner-to-drain connection, stepping which creates unwanted holes or nails below the waterline.
Retest the liner to ensure it is leak-free. Once done, completely drain the water and keep the shower dry.
- Install the top mud bed
Once the pan liner is completely installed and tested, a top layer of deck mud is added to support the tile floor. The mud should be packed in a way it is smooth and flat as possible from the wall. This helps to drain off the floor. To dry the deck mud, let it rest for about 24 hours.