Kerdi Showers and the Schluter Kerdi Tiling Membrane

Watertight and free from mold, this ceramic tile shower system is for you.

Kerdi Shower Advice and Installation Help at the John Bridge Tile Forums

- John P. Bridge (April 2004)

Yep, I’m a mud man. I’ve been building showers and all sorts of things out of cement mortar for over three decades now. Nothing like mud. It’s so permanent. I’ve run onto another method for building showers, though, that rivals the mud method. I like it so much, in fact, that I’ve been employing it with ever increasing frequency. Most showers I build nowadays are built using Schluter Kerdi, a membrane made by my friends at Schluter Systems, the folks who subsidized the cost of producing my book, Tile Your World.

Kerdi Installed Over Sheetrock

Kerdi Installed Over Sheetrock

Kerdi membrane being installed over sheetrock shower walls. The biggest single difference between a Kerdi shower and one built by other means is that it is completely waterproof. Moisture never has a chance to get into what’s underneath the tile and grout. There is absolutely no way the shower can leak, and it dries out very quickly after each use. This means that mold and mildew don’t stand a chance, inasmuch as those unsightly creatures need continuous moisture in order to thrive.

I bill the Kerdi showers I build as “mold-free,” but you have to do your part and dry the shower after each use. It only takes a minute or two, and if you do, I guarantee that you’ll not have a problem with mold, and you won’t have to clean your shower very often, either. Now if you choose not to hand dry the shower it will still dry out faster than showers built by conventional means, but a mold problem might develop at the grout joint where wall meets floor. That joint will retain water a little longer than other grout joints. It’s a good idea to dry the shower.

Kerdi Drain Set In Mortar

Kerdi Drain Set In Mortar

Kerdi-drain is set in mortar. The system revolves around the Kerdi-drain, a revolutionary invention in itself. The Kerdi-drain has a bonding surface that allows the membrane to be attached at the upper surface of the floor mortar instead of underneath it. The tiles are than cemented directly to the membrane, which goes from the drain across the floor and all the way up the walls to the height of the shower head in one continuous run. Waterproofing is attained by overlapping the membrane at all seams and by doubling the areas that are most susceptible to leaks.

Floor Ready for Kerdi Membrane

Floor Ready for Kerdi Membrane

Kerdi-drain and shower floor ready for Kerdi waterproof membrane.

Because the wall and floor substrates never see even a hint of moisture, the walls can be built of regular wallboard (plaster board). That’s right, good old sheetrock. Wood framing must be straight and true to accommodate the membrane system because there will be no other way to achieve a flat, smooth and plumb (vertical) installation.

Shower Completely Waterproofed with Kerdi

Shower Completely Waterproofed with Kerdi

Shower completely waterproofed with Kerdi membrane from Schluter Systems.
The tiles will be adhered directly to the membrane with thin set mortar.

I have found that there is no labor savings with the Kerdi shower because I spend a great deal of time ensuring the membrane is installed flawlessly. Installing the special drain and preparing a perfectly smooth mud floor for the membrane to ride on takes additional time. And so, I charge the same for a Kerdi shower as for a mud shower.

Labor prices start at $2,400 for a typical shower (roughly 3X4). We charge $250 to build the niches you’ll see in the pictures below, and $200 for corner foot rests (miniature benches). Full size shower benches are $250 in labor. Showers with door jamb returns and larger showers are more. (11-23-2011 — I no longer do tile work for hire. I still do consulting and tile job site inspections and reports.)

If your shower is adjacent to a garden or whirlpool tub, we can add that area to the project for an additional labor charge of $800 and up. This will include removable (disguised) access to the motor and under-tub plumbing.

Tub Platform Front Can Be Removed

Tub Platform Front Can Be Removed

The front of this tub platform can be removed to gain access to plumbing.

Material cost goes up a little when the Kerdi method is used. I would say that in a typical stall shower, the use of Schluter products will add $225 to $300 to the tile and materials bill. I consider this a small price to pay for a shower that is totally waterproof and highly mold-resistant.

It’s tough to give you an overall cost on a Kerdi shower (or any shower) until materials have been selected. I can give you a “ballpark,” though. For a complete tear-out and re-do of a shower with a garden tub area included you can expect to set yourself back $4,500 to $5,000. This will include your new glass enclosure. (You will need a glass company to do the enclosure.) You might spend a little less than this, and you can certainly spend more, but you will spend at least $4,000.

For a stand alone shower (with new glass enclosure) you can expect to pay $3,200 to $4,000. If you think you have to have a “frameless” shower enclosure, you can figure on adding at least $1,000 to the cost of your shower project.

In the big scheme of things the Kerdi shower costs no more than any other shower, and its benefits cannot be matched. I recommend the Kerdi shower. Let’s do it. :-)

Following are some shots of showers and features of showers done with the Kerdi method. You cannot distinguish showers constructed in this manner from those constructed by other means.

Kerdi Shower Example 1

Kerdi Shower Example 1

Kerdi Shower Example 2

Kerdi Shower Example 2

Kerdi Shower Example 3

Kerdi Shower Example 3

Kerdi Shower Example 4

Kerdi Shower Example 4

Kerdi Shower Example 5

Kerdi Shower Example 5

Kerdi Shower Example 6

Kerdi Shower Example 6

Kerdi Shower Example 7

Kerdi Shower Example 7

Kerdi Shower Example 8

Kerdi Shower Example 8



My new ebook on Kerdi showers is now available for download at the Tile Your World Online Store. It is an advanced tile setting book intended for people who want to build their own Kerdi shower. The price is $9.95. You can read about the book at The Kerdi Shower Book Web Site.

Added 10/31/2011:  Part One of Tile Bathroom Remodeling explaining the uses of Schluter Kerdi-board is now on sale. More information at KerdiBoard.com

See also: Accessible Showers

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