Shower Pan/Common Wall with Type X drywall: How do I waterproof? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile

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NMMI
09-15-2007, 04:10 PM
Here's the challenge: What do you do with a common wall in a shower that is made up of 2 layers of 5/8" Type X sheetrock if adding a layer of Hardibacker/Durock will make the wall unnaceptably thicker? Here's the story:

The builder/subs tiled over the outer layer of Type X sheetrock w/no waterproofing (thus the remodel). The 36"x42" fiberglass base was damaged during removal and is not available locally, so I'm building a pan with deck mud/PVC. I've removed the tile/Durock/Type X sheetrock 42" up the wall. Hardibacker will go on the knee wall and front of the shower up to about 42" (green sheetrock above that on the front of the shower).

The PVC liner needs to go between the two layers of 5/8" Type X sheetrock and all I can think of is using Redguard to seal both the inner and outer layers of 5/8" Type X (not sure if this will affect the fire rating). Adding 1/4" hardibacker will make the wall thicker and the pre-existing custom shower door/insert/return too wide ($1k to special order a new one if I can't cut it down to size).

Any ideas?

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ddmoit
09-15-2007, 04:13 PM
Welcome to the forum, Jason. :)

Are you familiar with Kerdi? It's a water proof membrane that can be applied with thinset directly to drywall.

NMMI
09-15-2007, 04:18 PM
Thanks Dan.

I thought it was an interlocking liner system that goes from the drain up the walls. One challenge is I'm on a tight timeline, bought all the materials, and plumbed in an Oatey 3-piece drain. The other challenge is the 36"x42" pan. Any thoughts on the Redgard?

Steven Hauser
09-15-2007, 04:50 PM
Hi Jason,

Do yourself a favor and follow Dan's suggestion, and this one as well. Always make time to do it correctly the first time.

:)

NMMI
09-15-2007, 04:56 PM
Steve,

I'm with you on doing it right the first time. I don't think Kerdi makes a 36x42 shower pan. Can you cut the 48x48 to size or can you use the Kerdi membrane with a deck mud/PVC pan?

Steven Hauser
09-15-2007, 05:04 PM
Hey again Jason,

KERDI is the bright orange sheet membrane not theshower pan.
here are a couple of links

KERDI
http://www.schluter.com/8_1_kerdi.aspx

shower pans

http://www.schluter.com/8_3_kerdi_st_sc_sr.aspx

ddmoit
09-15-2007, 05:22 PM
Jason,

Schluter makes some preformed pans that you can Kerdi over, but in your case, it's probably best just to make a slope out of mud to be covered in Kerdi. Outside of commercial applications, I'd say most Kerdi showers are done with mud pans.

NMMI
09-15-2007, 05:41 PM
Thanks guys. To maintain the thickness on my knee wall and front wall, I'm guessing I'd use Hardibacker. On the common wall with Type X drywall I'd use the Kerdi. Or should I drywall and Kerdi all the walls.

Can I get away with the Oatey drain...it's in 3" concrete (but I can bust it out).

I thought there was a link to a Kerdi e-book - would you mind posting the link?

ddmoit
09-15-2007, 05:48 PM
I would Kerdi everything. You really have to use the Kerdi drain as well. Some say it is the single best thing about Kerdi. You'll end up with a completely water-tight shower.

NMMI
09-15-2007, 06:14 PM
Thanks Dan. The shower is tiled up to maybe 8' over green drywall and Type X and I've removed the tile up about 42". Do you think I should just remove and redo it all?

This builder was really cutting corners (got sued by the condo HOA for construction defects and lost).

Do you have a link to the Kerdi e-book?

ddmoit
09-15-2007, 06:31 PM
Here's a link to the e-book: http://www.tileyourworld.com/catalog/product_info.php?products_id=66

I'd remove all the tile and do everything right this time. It's the last time you'll have to mess with it - unless you get sick of the tiles.

cx
09-15-2007, 06:33 PM
The Kerdi eBook is in our store, way down at the bottom, Jason.

Look here. (http://www.tileyourworld.com/catalog/product_info.php?products_id=66&osCsid=f9241c5cd3838ec4d5bf8c693d3c9859)

Or look there where Rapid Dan is pointin'. :)

Rob Z
09-15-2007, 06:46 PM
Hi Jason,

The party wall that has the Firecode drywall...is it built as a stand alone wall...meaning is it built in between your unit and the unit next door? If so, I would not use the wall for anything related to your tile installation.

NMMI
09-15-2007, 07:22 PM
Thanks for the links CX and Dan - I'm buying it now.

Rob, the wall is a shared wall and I believe it has two layers of firecode drywall on each side (our condo and condo next door). I don't have a choice but to put the shower where it was before, but I'm going to replace the two layers of damp Type X drywall on my side of the wall, then do the Kerdi system over the outer layer.

Any preferred distributors for Kerdi?

e3
09-15-2007, 07:24 PM
nobleseal or any of about a 15 other products would also work...
Look for a membrane that meets ANSI 118.10

ddmoit
09-15-2007, 07:35 PM
Jason,

You said you were on a tight time-line. One of the fastest and reasonably priced Kerdi distributors is Tile-Experts (http://www.tile-experts.com/) . Excellent customer service too - you tell them what you're doing, and they'll sell you only what you need.

Rob Z
09-15-2007, 08:34 PM
Rob, the wall is a shared wall and I believe it has two layers of firecode drywall on each side (our condo and condo next door). I don't have a choice but to put the shower where it was before, but I'm going to replace the two layers of damp Type X drywall on my side of the wall, then do the Kerdi system over the outer layer.


Hi Jason,

What I am referring to is a method that is common here where I live...the buildings are built separately, and then another crew comes in at a later date and installs steel track, insulation, and Type X, to the specs required by code for the fire rating. These wall are not attached to the main part of the building in any meaningful way (other than some clips and the paper tape in the corner of the drywall). If the membrane that you choose, whether it is Kerdi, Noble TS, RedGard, or whatever, is wrapped around that corner....then the inevitable movement of the wall relative to your unit is going to ask the membrane to do something that it isn't designed to do. :(

Both of the town houses that I owned prior to my current house were built this way, and it caused no end of problems in the corners where the walls met the party walls. :(

Things might be built differently in your area, but what I am describing will definately cause problems for you if your building is built this way.