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The Importance of Waterproofing

The Importance of Waterproofing

Waterproofing is the foundation of a successful, long-lasting shower.

Contrary to popular belief, traditional shower systems are NOT completely waterproof.

Most shower systems use a “pan-liner” to waterproof the base of the shower that is encased in a bed of mortar. Unlike Schluter’s KERDI waterproofing membrane, which is applied directly under the tile coverings, pan-liners are positioned in the middle of the mortar bed, which is then tiled over.

Since tiles and the grout lines around them are porous, water and vapor penetrate through them into the upper portion of the mortar bed that is above the pan-liner and also into the walls of the shower. This leaves the mortar bed and building materials in the walls susceptible the threat of mold and efflorescence. However, you can easily eliminate mold growth and the costly repairs it brings by building your shower with components from Schluter’s KERDI product line.


What is KERDI?  What are the advantages?

KERDI is a complete waterproofing system created by Schluter that can be used to waterproof showers and other tiled areas that may be exposed to water or steam. The KERDI product line includes waterproof membranes, boards, seals, drains and prefabricated substrates that can be integrated together to built a complete shower or added to a mortar bed or “hot mop” application to add full waterproofing to a more traditional system.

All components of the KERDI system are waterproof and can be tiled over directly, preventing moisture from penetrating into the materials below and enabling the tile and grout above to dry completely.


KERDI Waterproofing Membrane

KERDI membrane have a thin, pliable polyethylene construction that makes them easy to install over any surface using unmodified thin-set mortar. They come in rolls for waterproofing large areas and strips for waterproofing joints/edges.

KEDI Membrane






KERDI seals come preformed and ready to install around pipes and mixing valves that protrude through the walls of showers and steam rooms. Complete the seal by applying KERDI-FIX between the preformed membrane and the pipe/mixing valve to keep moisture from seeping into the back panel and damaging your plumbing and walls.



KERDI-BOARD building panels are a great alternative to cement board and other traditional building materials that are susceptible to old growth. The panels are waterproof and vapor retardant, just like KERDI membranes, so they can be tiled over directly, cutting down on installation time and giving you peace of mind without having to add extra waterproofing. KERDI-BOARD comes in a variety of thicknesses and configurations. It is also lightweight and can be cut with a regular utility knife, making it easy to build custom showers, bathtubs, counters, countertops, and vanities in a fraction of the time it does with traditional building materials.

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