Kerdi Shower Pan Confusion
The Kerdi shower pan is one of the ways to skip most of the mortar work you usually get into when doing a shower pan installation. It's a way to a waterproof shower with some real advantages as you will see as you read on...
The whole Kerdi product line is confusing, at least to me it is. For one thing, there's the name. Sometimes it's Kerdi, but then again it's Schluter. But then you see Schluter-Kerdi. I think I've seen Kerdi-Schluter. Then there's Schluter System. So it's all very confusing.
Then the so-called system is confusing too.
As I see it though, the best way to look at it is you get this waterproof liner membrane that goes on top of all kinds of things to make a waterproof layer.
You can put that liner membrane on the floor; it can go on walls; or put it on the ceiling of a shower.
In short, the core piece of the Schluter Kerdi, or whatever you want to call it, line is the waterproof liner membrane.
By putting the waterproof layer on top of the shower base you avoid the water soaked base as you will get with a typical masonry shower. See with a mortar shower the liner is down in the floor and all the base above the liner gets soaked over time.
OK...
So you have this nifty waterproof liner membrane you can use.
The Kerdi Shower Pan Options
One option in the whole system is to use the Kerdi "foam" base or what they call a substrate.
That consists of a piece or two of foam that is about the same size and shape as the mortar would be in a normal shower. Unlike some tile shower kits like the Tile-Redi, the base or substrate from Kerdi, or Schluter, is NOT waterproof. It just serves as the form for the base. What make it waterproof is...
the waterproof liner membrane material.
All that gets combined too with a special drain made to be used with these pieces.
Like most of these shower base kits, the foam parts only come in selected sizes. You can trim to fit and you can modify a little but there IS a limit to what you can do with the base itself.
This leads to option 2 with the Schluter Kerdi showers.
Go custom all the way with the membrane and a custom built base.
You can to get any size base, build the base up with mortar to any size.
What advantage is that over a normal masonry base shower?
Here's how...
- Just one layer of mortar, not two
- No liner built into the mortar
- Liner membrane goes on top
- Not so many tricks to install
- Less skill needed
- Less cure time with just one layer
- Since liner is on top the base does not get water soaked
Using mortar for the base offers a number of advantages and gets a custom shower with less trouble and less money than some other options. It's not a foam shower pan but it sure can be a waterproof one.
As you can maybe see the Kerdi shower pan is at least confusing. Using the several components from these folks you can build showers that are more nearly waterproof than what you get with many other shower types.