I second the GoBoard tile backer from John Manville. Lowes carries it, stocked in some stores and orderible in others.

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is cost a real issue ?

 

I'd go with 1/2" concrete board, installed strictly per the manufacturers specifications, and then RedGard, installed strictly per the manufacturers specifications.

We just did this using USG Durock concrete board...

 

Ya know......We probably all like what we know best.

I'm an old timer....and have used the old systems with hardy or cement board over a waterproff 6 mill plastic, hand poured preslope/liner/top slope bed, hardy with redguard etc etc.

But most recently I've done a couple of "family" jobs with some of the new stuff. I really like the tile ready sloped beds, yes more expensive but one hell of a lot easier.

For walls, there is this new waterproof "Go Board". Lightweight, not to expensive, clean working, similar in principal to Kerdi but less expensive. Tape the joints and redguard only the joints, The board is your waterproof barrier.

Your idea of not mixing systems in general is very sound....but I used a presloped bed from KBRS (custom made or trimmed to fit.....not sure my wall system is truely compatible to Kerdi systems.....but Kerdi is pricy and I do not think superior to other systems, assuming all systems are done correctly.

(I have no idea why someone would use greenboard and redguard, why not use stronger regular sheetrock, your waterproof barrier is the redguard. Now in older times, some production building was done just with greeboard and a 6 mill barrier, that system ws crappy.)

 

Thank you guys for the thoughts.

Fix'n It---Cost is not the most important issue for me. It would be nice if I could do it for cheaper---But I'm more concerned that it turn out really good and be trouble free. I've done a lot of stuff, but this is my first shower. The idea of using a prefabricated pan is what led me to kerdi. It seemed like it might be a good idea to keep things as simple as possible this time through.

Henry Mac---Did you do your pan from scratch? Do you think the concrete board would blend ok with a prefab kerdi pan? What is the advantage of using the concrete board, its strength compared to sheetrock or green board?

MTN Remodel---Thanks for the thoughts. I will look up the products you mentioned.

 

Henry Mac---Did you do your pan from scratch?

Yes, it was done by a local guy.

Do you think the concrete board would blend ok with a prefab kerdi pan?

I don't know. I have no experience with the prefab kerdi pan. But the concrete board is 1/2" thick, just like sheetrock and green board.

What is the advantage of using the concrete board, its strength compared to sheetrock or green board?

Take a small piece of sheetrock, of green board and a piece of concrete board and toss it in a bucket of water. Leave it for a day, then pull them out. That will show you the advantage of concrete board. Yet another layer of protection from water intrusion.

There was a time when a shower was just a single shower head, permanently attached to a wall. But since hand held wands and multiple shower heads are popular the amount of water, and humidity, in a shower is 10 fold what it used to be.

So having waterproof redundancy is important.

 

The Kerdi pan is the way to go for me. There are other presloped pans, but the Kerdi drain is very simple and effective to use.

As for the walls, I've used Kerdi membrane over cement board, Kerdi membrane over drywall, and Kerdi Board. If I never have to cut another cement board wall I'll be happy (same for floors - I used Ditra - but I digress). Cement board is a heavy mess compared to drywall, and drywall is a heavy mess compared to Kerdi Board. Kerdi Board is expensive, but I can justify it because it saves time, and it's a joy to use. If you want to go to the extra effort of putting the membrane over drywall, there is no need to use greenboard.

If you mix something like GoBoard with Kerdi, I'm not sure how you waterproof the shower pan seam. Kerdi is waterproofed because of the interaction of the thinset with the fleece lining, and GoBoard does not have the matching fleece. I don't think you can mix and match the waterproofing techniques. For example, the type of sealant recommended for GoBoard is not going to work as well with the fleece lining on the Kerdi pan. So call Schluter technical support on that one.

 

I figured I had two real choices for the pan----a prefab pan that is trimmable, or mud a pan from scratch. The drain is an existing drain in the center of a 32x32 space, set in concrete, and while it is centered, I'm sure it is not nasa perfect. The shower will have two tiled walls and two glass walls.

Yeah I wasn't sure about mixing other brands with kerdi, precisely because of that seam at the pan. I do like the price of that GoBoard, though. They sell it at Menards near me.

I'd rather not use cement board unless there is a really compelling reason to do it. Granted nothing should be banging into the shower walls, but are the kerdi panels when tiled strong enough to be pretty durable? I'm sure the cement board is stronger.

I like that the kerdi panel is itself the waterproof barrier; there is no substrate that can be affected. Well, other than the studs, if water got in there.

 

I'd rather not use cement board unless there is a really compelling reason to do it. Granted nothing should be banging into the shower walls, but are the kerdi panels when tiled strong enough to be pretty durable? I'm sure the cement board is stronger.

I like that the kerdi panel is itself the waterproof barrier; there is no substrate that can be affected. Well, other than the studs, if water got in there.

With Kerdi, it's more about the overall structure when you're done that makes it strong, not the Kerdi Board per se. Schluter refers to this as the "tile assembly", meaning that everything works together - once you have the board, attached at no more than the specified stud spacing, along with thinset, tile, and grout, it all becomes a hard structure. Is cement board stronger? Yes technically. But then 2x6s would be stronger in your walls than 2x4s. Yet 2x4s are almost always good enough.

For waterproofing, you screw the Kerdi board in with their screws and large washers. These need to be covered with a piece of Kerdi membrane and thinset in place, so no water can reach the studs at any point.

 

Georgia pacific makes denseShield tile backerboard which has a water proof acrylic covering and National Gypsom makes a similar product. locally a 5/8" thick 4x8' sheet is $32. any drywall supply store should sell it. not sure if big box hardware stores will. That's what I will be using when I do my custom shower. For the base I found a tile ready base for $225 on facebook marketplace. I was going to go Kerdi, but this was cheaper, stronger and more water tight.

 

Hmm. How does 5/8" backerboard transition to standard 1/2" drywall?

Whatever base you found is not cheaper than a Kerdi pan, and it's not more "water tight" either.

https://www.lowes.com/pd/Schluter-Systems-Kerdi-Shower-T-TS-TT-Styrene-Shower-Base-72-in-W-x-48-in-L-with-Center-Drain/1001052192