By Request

by John

So, the bathroom is finally ready for tile. My sister and I were chatting last week, and she was interested in the orange liner you could see here. For those of you not interested in some boring remodeling stuff, you can skip to the end. For the one or two of you left, the liner is Schluter Systems Kerdi. This stuff is the best!

To do a tiled shower traditionally requires 2 - 3 inches of concrete poured at the right slope to create the shower pan. You have to make your best guess at the drain height to match the tile height. Us DIYers don't have the experience to guess right. It's a lot of work, it's not completely water tight, and usually only lasts 15 years.

The Kerdi shower system comes with a pre-shaped styrofoam shower pan that is 1/4 - 1 inch. After that, you line the entire shower (walls and floor) with the orange liner that makes the shower completely water tight, and its guaranteed to last 25 years. It comes with an adjustable drain that is the exact size of 3" tile; no cutting for the drain. I learned from the vendor that you can line a cardboard box with Kerdi, fill it with water, and the cardboard doesn't get wet! Unless you splash water everywhere. ;) Check out John Bridge's website for more details on installing Kerdi.

I learned a few things installing Kerdi that you may want to remember:
1) The pre-shaped corners in the shower kit are inside the drain box. I didn't check and had to do the corners the hard way. The inside corners for the bottom of the shower are not critical; you can overlap the Kerdi band on itself just as easy as the pre-shaped corner. However, outside corners for windows or doorways are MUCH easier with the corners. I found my corners near the end and wished I had used them earlier. You only get two outside corners, so buy as many extras as you need for your doorways and windows.
2) Use only unmodified Thinset. Fortified Thinset is great stuff everywhere but the shower. The vendor I worked with stated that the silica in the fortified Thinset is more vulnerable to mold/mildew. Your shower will last longer with unmodified Thinset.
3) Mix the Thinset a bit thin; think toothpaste. Usually Thinset is mixed to peanut butter consistency, but you want it a bit thinner so you have time to spread it on the wall and squish the Kerdi into the Thinset
4) Buy a J-roller. It took three times as long to squish the one piece I tried with a 12" trowel as it took with the roller. These rollers are used for laminate, but they work great for the Kerdi.
5) The Kerdi system is a bit spendy. The kit comes with enough for a standard 48 x 48 inch shower. Any more, like our tub, and you will need to buy some extra.
6) Consider using the Kerdi all the way through the doorway into your shower. This gives you a "floor mat" under you tile outside the shower that is water tight and will prevent water damage.

I think that's it! Good luck with your shower remodels.