Evolution of the Watertight Shower
By Kimberly Rielly
The hygienic and maintenance-free characteristics of finished tiled coverings account for the prevalence of this ideal surface in bathroom and, specifically, shower applications. However, because the integrity of the tiled surface relies upon a system of water management to protect the sub-shower assembly from moisture penetration, tiled showers have always represented a considerable challenge for installers.
The traditional method of installing a shower receptor has some obvious drawbacks. Typically, an installer must place a mortar bed, sloped to the weep holes in the sub-drain, prior to installing the pan liner. Once this "pre-slope" has cured to the point where it can be walked upon, the pan liner is installed - with its tenuous connections to the clamping ring in the sub-drain, seaming, and carefully fitted corners around the curb area, all of which must be bonded with the appropriate solvent-based bonding agent. Each of these steps must be completed, and the weep holes protected from being clogged with mortar, before the shower pan is ready to receive the setting bed for the floor tiles. This conventional methodology requires substantial time and labor.
However, since shower pan liners are placed below the mortar setting bed in a conventional assembly, receptors successfully constructed in this manner allow moisture to saturate the mortar bed. This can increase the risk of leakage, cause efflorescence, lead to deterioration of the mortar bed itself, and foster bacteria and fungus growth.
The industry responded to this situation by developing bonded waterproof membranes, which bond directly to the mortar bed and protect it from becoming saturated. In 1987, Schluter-Systems supplied the industry with an effective seaming and waterproofing solution, Schluter-KERDI. KERDI is the most user-friendly, sheet-applied waterproofing membrane in existence. Because it is so thin and lightweight, it hangs as easily as wallpaper.
KERDI ensures that floors, walls, and inside and outside corners are simply, effectively and permanently protected from moisture penetration.
Although bonded waterproof membranes are an ideal waterproofing solution, the incorporation of bonded waterproof membranes in floor drain installations presented yet another challenge: In a traditional assembly, conventional two-piece floor drains are designed to connect to shower pan liners below the mortar bed, and do not allow a secure, watertight connection to bonded waterproof membranes at the top of the drain assembly.
Hence, the challenge was to develop an integrated system in which the individual components collectively formed a bonded watertight assembly. The introduction of the revolutionary Schluter-KERDI-DRAIN in 2001 achieved this objective. The KERDI-DRAIN floor drain was designed specifically to ensure a simple and secure connection to Schluter-KERDI bonded waterproof membrane at the top of the assembly rather than below it, reducing the risk of leakage, efflorescence, and fungus and bacteria growth. In addition to these benefits, KERDI-DRAIN also includes a fully adjustable square drain grate to allow precise tile layout.
In and of itself, this system provides both superior functionality and tremendous time and labor savings. However, in order to provide the installer with the ability to achieve a completely watertight assembly both with or without a mortar bed, Schluter-Systems has recently introduced the Schluter-KERDI-SHOWER-ST tray and -SC curb.
For shower floors constructed with mortar, KERDI-DRAIN eliminates the process of pre-sloping the floor. When used in conjunction with the KERDI-SHOWER-ST tray and KERDI-SHOWER-SC curb, the mortar setting bed is eliminated altogether. Schluter-KERDI-SHOWER-ST and -SC are comprised of lightweight expanded polystyrene (EPS). The -SC curb can easily be cut to length, and the -ST tray is pre-sloped and specifically designed to accept the KERDI-DRAIN for a secure, watertight connection.
The system is completed with Schluter-RONDEC and DILEX profiles. The extensive Schluter-DILEX family of prefabricated movement joints includes cove-base solutions for shower applications. Schluter-DILEX-EHK in stainless steel and -HKW in colored PVC provide maintenance-free floor/wall and inside corner transitions, eliminating the need for caulking. Schluter -RONDEC protects and finishes outside corners, and is available in a large variety of colored PVC and metal finishes, including stainless steel.
With KERDI and KERDI DRAIN as its foundation, the Schluter Shower System eliminates the risk of failures due to both vapor and water penetration, is maintenance-free, and dramatically reduces total installation time to ensure success and make shower installation easier than ever.