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Waterproofing is often one of the most overlooked steps yet critically important.

Updated: Jun 26

Waterproofing is often overlooked as an insignificant step when completing a major renovation project.


However, the actuality is that you must. Correctly install your shower pan liner when renovating showers and baths to avoid dealing with costly water damage down the line. Not only will you have to repair existing damage or replace fixtures ruined due to leaking water, but you will also be forced to re-do already completed work to ensure a safe and long-lasting finish. To help avoid this headache later on, today we'll walk through how to properly install your shower pan liner; so regardless of whether you plan DIY projects or hire professionals for any large job around your home, keep these steps in mind!

Install drain base


First, insert the drain base into a pre-made hole, with a recommended size of 4-1/2 inches for Oatey tile shower drains, and secure the flange to the subfloor with screws. If your drain is assembled, loosen the bolts that connect the clamping ring to the flange and remove the clamping ring. However, make sure to leave the drain plug at the center of the drain. Should you lack a drain plug, cover the drain hole with duct tape as a temporary solution., but be sure to obtain a drain plug later. Note that using felt paper with the pan liner is not recommended, as the petroleum in the felt paper can react with the liner, resulting in cracking or brittleness and ultimately leading to leaks.

Prepare slope


When preparing the slope for a shower bed, you can choose between mortar or Oatey's Perfect Slope. If you want to perfect your cement shower bed construction skills, I'd be delighted to assist. By learning different techniques to slope your shower bed to perfection, you can ensure that your shower is always water-ready and looks like new.

Whether tackling a DIY project or looking to brush up on your handyman skills, having a little extra knowledge on creating the ideal slope for your shower bed is an invaluable asset to your repertoire. Oatey's Perfect Slope is recommended. If you use mortar, pour it onto the subfloor at a ¼ inch per foot slope, sloping inward from the wall framing to the top of the drain base. Once you've poured the mortar, follow the instructions for curing it.

Perfect Slope

Consider installing Oatey's Perfect Slope onto your subfloor to save time and avoid complications. Be sure to adjust the Perfect Slope to fit the dimensions of your shower, including around the drain, for a smooth and seamless fit.



Measure scrap pan liner for the curb.


Measuring the width of a curb before pouring is essential. To simplify the process of taking measurements., our pan liners come marked in 6 in. increments. Measure the inside and outside heights of the curb and the top width, then staple a piece of liner over the curb using these dimensions. Please ensure that it fully covers the top. Both sides. Add the inside curb height to the outside curb height and top width to get the total curb width.



To ensure precise sizing, measure and cut the pan liner accordingly.


Begin by ensuring that the pre-sloped mortar bed or Perfect Slope is dry and clear of debris. Then, make a five-inch mark up from the curb onto the wall framing and measure from that point down to the mortar bed to ascertain application height.

Subsequently, place the shower pan liner on a flat surface and measure and mark the length and width of the mortar bed as per the diagram below. Lastly, cut the pan liner according to your markings.

Total mortar bed length: 2x application height + mortar bed length

Total mortar bed width: total curb width + mortar bed width + application height

This regimen ensures accuracy, cleanliness, and feasibility during installation.



Install pan liner


Pro-tip for installing shower pan liner:

  1. Pre-fold the edges before starting for an easy application.

  2. Flip the liner over and make marks on three sides according to the required height.

  3. Fold the sides at each spot.

Remove the test plug from the drain and drape the pan liner over the mortar bed and the drain base. Ensure that the edges facing the wall have been folded according to the correct height of the application. After aligning the liner to the center, locate the drain plug and cut out an X shape over the four bolts for the clamping ring screws. Also, cut out a hole over the drain hole.



Instructions for assembling the drain base.


First, fold the pan liner halfway to expose the drain base. Next, apply silicone caulk to the surface of the inner flange. Afterward, gently fold the liner back over and push the bolts through the X shapes in the liner. Then, screw the clamping ring down over the four bolts. Finally, tighten the bolts until the ring fits snugly against the liner. Eventually, replace the test plug.


To properly secure the pan liner, fold the corners and attach it to the rough framing.


Pro Tip for maximum waterproof protection: Staple the top ½ inch of your liner and fold the corners, securing them with pan liner adhesive (Oatey X-15 for PVC liners, Oateyweld for CPE liners). Then, staple the liner to the wall framing. This ensures not only water tightness but also a durable waterproof barrier.


Attach the pan liner to the curb.


To construct a waterproof shower curb, cut two pieces of scrap liner to match the width of the curb and be at least 6 inches tall. Adhere both pieces to the top of the curb, with half on the curb and half on the wall framing. Then, cut the liner at the inside corner, and affix it horizontally over the top of the scrap liner. Next, staple the liner onto the wall framing, removing any excess hanging outside the shower's dimensions. Next, install the pan liner for the mortar bed over the curb, affix the lot, and staple the curb's outside again.


Conduct a flood test.


Once you've let the adhesives cure overnight, verifying that your shower bed is genuinely watertight is essential. Begin by securing the test plug and pouring water into the shower bed, filling it up to the recommended height of the curb. To allow sedimentation, leaving the water undisturbed for at least some time is recommended for two hours, and carefully inspect for indications of leakage. If the water hasn't dropped, the surrounding area is dry, and there are no leaks from the ceiling (if you're on an upper floor), then no leaks are present. Finally, remove the test plug to drain the water.

Suppose the shower bed passes the leak test. If that's the situation, then you can anticipate some thrilling stages during your shower installation., including selecting your drain and drain height, applying a mortar base on top of the pan liner, adding thin-set adhesive between the mortar and tile, choosing your tiling, and finally installation. If you encounter difficulties during your building.



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