Traditional Shower Pan 

 
Leaks - Efflorescence - Clogged Drain - Bugs - Structural Cracking 
The shower pan is the underlining issue
There are 4 important key steps to correctly installing a traditional tiled shower pan system.

1. Pre-slope - 
The shower pan cannot sit directly on a flat/level subfloor, this is the most common mistake and step most installers are unaware of. A pre-slope must be installed underneath the shower pan to force water to the drain. Later if any grout cracks, water will pass through to the pan and just sit on the bottom of the flat pan. This simple step prevents the water from sitting on a flat surface with no slope for water to drain. Then the concrete sits in the pan constantly soaked, creating a cesspool for bacteria and efflorescence to grow.

2. Shower pan - 
Is a rubber liner designed to stop water from escaping the shower area. The shower pan must sit on a slope, connects at the drain and goes up the walls, wrapping over the curb and bench without cutting corners. Although this thick rubber liner gets bulky when folding corners, so most will cut the excess and seam seal the areas. Not wrapping over the bench, screwing threw or puncturing the pan, faulty connection at the drain and failing seam seals our the most common issues with traditional shower pans that usually don't show problematic until years later. 

3. Drain - 
There are 3 key parts to the drain: flange, weep holes and screen. The flange is made of 2 pieces, the bottom screws to the sub floor and connects to the pipe below. The top secures the shower pan between the two and is threaded inside to screw in the screen. The weep holes are small drain holes for water to escape from the pan. The screen screws into the flange, stretching through the concrete gap and creating a level surface with the tile. The screen can be a decorative feature, stops larger debris and creates access for cleaning/maintenance. Clogged weep holes and improperly sealing/securing to shower pan is the most common issue to leaking showers. Most installers simply apply concrete all the way to the drain without pee-gravel over the weep holes for water to drain. Over-cutting the pan for the flange can lead to gaps at a very important seam. Over sealing the flange can clog the weep holes and underselling will allow water to leak though underneath.  

4. Waterproofing -
This can be the most important step, if everything else underneath is not perfect, waterproofing will stop water from ever reaching the pan. This step is considered an upgrade or extra step most installers simply skip.
Underneath waterproofing is a liquid/gel shower pan liner that you apply directly to the concrete, creating a secondary shower pan, therefor the mud-bed will act as the pre-slope and prevent the whole cesspool process.
Surface waterproofing is the process of using superior epoxies, coatings and sealers for the grout and tile preventing water from passing through the tile/grout surfaces. 

Combined waterproofing will greatly improve longevity, with much less maintenance and cleaning problems later.


If a shower pan is installed correctly: 
Water that passes through grout/tile cracks or gaps should stop at the waterproofing membrane underneath the tile. If not water will pass through the concrete and collect on the rubber pan, (sitting on the pre-slope) forcing to drain through the weep holes. Note: (Any cracked grout or tile should be repaired (keeping the surface waterproofed) before using or wetting)