Traditional Shower vs. Schluter Shower

Waterproofing is the foundation of a successful tiled bathroom.  Moisture-sensitive construction materials such as wood framing, plywood or OSB sheathing, gypsum, wallboard, etc. must be protected from water and vapor penetration.  Wet areas increase the potential for mold growth if effective moisture management is not provided.  The key to mold control is moisture control.

Traditional Shower Installation

Pan Liner Method

The traditional method for installing tiled showers is both time and labor intensive, requiring many steps to ensure success.

First, a mortar bed is sloped to the weep holes in the drain. The waterproofing membrane, called a pan liner, is placed over this “pre-slope” and clamped into the drain. The pan liner is carried over the curb and up the walls about 3 inches above the curb. A moisture barrier, such as tar paper or plastic sheeting, is placed on the walls and lapped over the pan liner.

While this completes the waterproofing installation, additional prep work is required because the waterproofing materials used in this system do not allow for the direct application of tile. A mortar bed is placed over the pan liner, and the walls are covered with mortar or tile backerboard. These materials provide a support layer and bonding surface for the tile.

Contrary to popular belief, the tile covering itself is not waterproof. When the shower is in use, water and vapor will penetrate the mortar bed and tile backing on the walls. This moisture must seep through the mortar bed to the sloped pan liner and exit through the weep holes in the drain. In this way, the assembly can be described as a “water-in/water-out” system.

Mortar beds are a great option that require fine attention to detail. When even small details are overlooked, issues can quickly arise; water may accumulate with no way to escape which increases the potential for mold growth within the system.

Schluter Shower System

Bonded Waterproofing