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Shower backerboard question

Reit38

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Nov 12, 2011
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Iowa
Attempting to tile my first shower and have a a outside 90 of a shelf. I know on sheetrock you use a cornerbead but what do you do with wonderboard

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Sovereign-1

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Mar 5, 2014
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unless you put a plastic vapor barrier underneath. Otherwise you will need a topical one (kerdi, hydroban, redguard, etc)
 

ddurrett896

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VA
If you're going to do Kerdi, drywall you is recommended as a substrate. From what I've read it's difficult to install Kerdi on cement board, and unnecessary.

Wet it down before you thinset.

Drywall works, however a water leak will destroy it and the tile will go with it. Cheap insurance.
 
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Reit38

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Iowa
I plan on using redguard to roll on and have mesh cement board tape for the joints

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TexasShooter

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East Texas
Kerdi is for sure a perfectly fine, easier DIY system. But for the contractor supplying the materials in his bid can have a hard time being competitive.

And a properly installed mud shower, or hardi/wonderboard is just as strong as Kerdi. IMO.


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hefnerconstructionlc

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Kansas
We build lots of showers, if your doing a tiled base. Then absolutely Kerdi. Redguard has lots of weasel clauses. Requires multiple coats for specific mill thickness. It is also sort of mastic/rubber kind of product. I think over the long term its a real possibility it will re-emulsify. Kerdi and mortar will not, in fact they are more likely to strengthen over time.
 

TexasShooter

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The only way I could see it re-emulsify would be in a steam shower, which redguard is not to be used there. Ive been in the family flooring business my whole life, and have been actually working in it little over 10yrs. That being said I have never heard anyone have a problem where it did that. It does dry to a rubber like texture, and if done properly could technically be used instead of your vinyl shower pan.

Also I don't understand the mastic comparison. The only thing the 2 could have in common is both being a "wet" product in the bucket.


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hefnerconstructionlc

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Sorry Texas, you are correct with re-emusify question of liquid membranes. The Liquid applied membrane should not re-emusify if proper cure time is followed. This includes between individual coats and subsequent setting of tile on the liquid membrane. My concern would be with the liquid applied material losing its adhesion to the surface and become compromised due to moisture migration. Its only my opinion, but I feel there are lot of ways to get the install wrong and have hidden problems. Don't get me wrong if everything is followed to the T, a liquid applied membrane works fine. I just think for ease of install, and piece of mind, the Schluter products are easier to get right.

https://sccpublic.s3-external-1.ama...814279786526/fcim-waterproofing-disasters.pdf
 

s14kev

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Dec 12, 2008
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I just finished a tiled shower and now am finishing a tub surround. Both are the first time jobs for me. I chose cement board and Kerdi for the tiled shower and now am doing cementboard with Mapei Aquadefense (like redgard/hydroban) for the tub surround. Kerdi is a little more work but provides supreme confidence about waterproofing ability. Despite being a first job, I am very confident that the shower floor and walls are completely waterproof. Since the tub surround does not seem as likely to leak as a tiled shower, I feel confident that a liquid membrane is sufficient.

As stated above, I did my 90 degree corners with alkali resistant tape and thinset. No bead required. With thinset, the corners are rock solid.
 

Dirtydan69

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San Tan Valley, AZ
I have installations properly done with membrane, mud beds or terrazzo and cement board that are over 25 years old that are still leak free and holding up well. I realize though that Kerdi is the way to go these days but, as someone else stated, it's very difficult to stay competitive.
 
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rayra

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Escaped from Los Angeles
Your mesh/thinset with some Customs Redguard works great


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That method worked well for me.

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Reit38

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Nov 12, 2011
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Iowa
Alright thanks. That's what I started the thread for was to find that out or if there was something better. And it turned into a kerdi debate

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ddawg16

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Jul 11, 2008
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S. California
Interesting take on Kerdi vs traditional.

My shower pan is the old Hot Mop...1/2" Hardibacker on the walls with 30mm tar paper behind it.....covered with tile...

That Kerdi stuff is expensive. I did hot mop on two showers for the cost of Kerdi on one shower.

But I should point out....hot mop is not the best choice in climates where freezing is an issue. I don't have to worry about it where I am.
 

TexasShooter

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East Texas
I will agree to the point to where the average DIY guy has a far better chance of a successful shower with the Kerdi system, but a properly done Hardi/Wonder/Redguard shower is just as strong.

Also Johnbridge.com is a very helpful forum for all tile related issues. If you are having a problem, or have a question, a quick search and I bet it had been covered on there.
 
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Todd.Brock

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Cincinnati
Man- I have wrestled with the Kerdi vs mud pan debate. I have a kit that is plastic that helps slopes the mud pan. I haven't started yet but I always wonder back to kerdi.

OP- I would use the mesh tape and then just make sure the shelf is sloped to shed water
 

ddurrett896

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VA
Man- I have wrestled with the Kerdi vs mud pan debate. I have a kit that is plastic that helps slopes the mud pan. I haven't started yet but I always wonder back to kerdi.

OP- I would use the mesh tape and then just make sure the shelf is sloped to shed water

I went with Kerdi and a mud pan with Kerri over it. My shower is 50sqft - no way I was buying the pre made pans.
 
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csp

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Mar 23, 2010
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Franktown, CO
An alternative to both mud pan and Kerdi pans. One piece, premade pans either in standard sizes or custom built. These do have the slope to the drain built into them. Just installed an 80x36 pan with the drain exactly where I wanted it. Walls are durock with the Mapei version of redguard.

https://www.showerbase.com/pages/kbrs-products
 

ddurrett896

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VA
I presumed you used a pan liner. Not criticizing, just curious...

You have two options:
1. Mud pan with plastic liner
2. Mud pan with water proof membrane on top

If you go with the liner, you need to build a pre-slope so the liner grades into the drain weep holes then do a second mud over the liner. I see a lot of "professionals" lay the liner on the flat floor and build the pan over. The water that gets thru the tile/grout/mud and pools on the flat floor. This creates a smelly, mildew mess.

If you go with a membrane on top (kerdi, redguard, Hydroban, etc), build one mud pan then cover and tile. I went with this because I'm more confident in the system and in the event I add steam to the shower, you will need a membrane and I'm covered.
 

a91syncro

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Dec 15, 2008
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Location
Stoughton, Wisconsin
I'll jump in here. I set tile for a living and have used both systems for installs. The problem that i have with the kerdi system is the layering of the material in the corners. This is not a problem with large format tile but is when using 3x6 subway tile. It (kerdi) tends to make the tile flare out in the corners. I know you could float this with mud but then just do this with regular mud and a waterproofer.
 

Radix2

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May 28, 2014
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the thumb!, MI
I've done Kerdi showers and like the system. On a recent build I used a product called Goboard - it is a foam core board like schluters kerdiboard and it was very nice to work with and weighs about 1/10 the cement stuff. The board is waterproof on its own, easy to cut and much much much nicer to work with than hardy or Cement board. You use polyurethane caulk to seal corners and seams. I bought it at menards.
 

Todd.Brock

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That makes sense. I have a plastic two part kit I purchased that helps define the slope of the mud bed, and then put in the pan liner, and then a second plastic frame to set the slope of the mud bed on top. Seems like a good system to me I just need to actually get up the gumption to rip the old stuff out and get moving.
 
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