Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Welcome to John Bridge / Tile Your World, the friendliest DIY Forum on the Internet

Advertiser Directory
JohnBridge.com Home
Buy John Bridge's Books

Go Back   Ceramic Tile Advice Forums - John Bridge Ceramic Tile > Tile & Stone Forums > Tile Forum/Advice Board


Thread Tools Search this Thread
Old 03-31-2013, 03:41 AM   #1
Registered User
Join Date: Mar 2013
Posts: 2
Kerdi Shower Pan Install

Hi Everyone:

Am a semi-experienced DIYer and decided to try my hand at renovating the bath in an old house I recently purchased. I have a couple of questions pertaining to the installation of the Kerdi system. It is very important I get this right, otherwise my wife will open up a can of whoop-ass (verbal and otherwise) on me if I screw this up:

1) Durability of the Kerdi Shower Pan -- The Kerdi shower pan system looks great, but when I spoke to some contractors about it, they were doubtful that the material would hold out over time, ie, it might sag given the nature of the material, as opposed to a material like concrete, and that the tiles would crack as a result. Does anyone have any longer-term experience with the durability issue? How has yours held out?

2) What to do about the difference in slope after cutting -- I understand that I can cut the Kerdi shower pan, but in my case, I would like to cut it evenly on just two sides. I have the 32x60 center drain model and the width of my bath, after studing and installing HardieBacker, will be around 48 inches, so I want to lop off 6 inches on each the longer side of the pan. Obviously, I don't want to cut off an equal amount on the shorter side, otherwise I will have a very narrow shower. My question is what could I do to build up the slope on the sides I have cut, so that they are at the same level as the shorter side of the pan? Should I use dry pack to build up the slope, or will the difference be negligible enough that I could simply use thinset to offset the difference?

3) I was planning on using the Kerdi membrane on the floor and around the edges of the floor for waterproofing, but then switching over to Laticrete to do the walls. The reason for this is just that the Laticrete looks a lot easier to use. My question is does anyone foresee a problem with combining both products?

4) Finally, I'm not sure, but I think I understood that installing the Kerdi tray, membrane, and Ditra on HardieBacker might pose a problem in that the HardiBacker might suck away moisture from the thinset too quickly for these items to set properly. Any experience there and if this is the case, what to do about it?

I appreciate your help in advance and apologize if I've throw too many questions out at once.

cjzullo is offline   Reply With Quote
Sponsored Links
Old 03-31-2013, 04:10 AM   #2
Executive Flooring
Registered User
Executive Flooring's Avatar
Join Date: May 2009
Posts: 471
Welcome CJ,

First off, you definitely dont want to upset the wife!

As for your questions;

1. I dont use the foam trays that much but the few that I have out there have held up just fine. When you use mud beds all the time like most pros do, its really not that much more work for us.

2. Where you will not have to adjust the slope to much, use just some thinset on the tray to adjust it, let it dry, and then put the kerdi down as you would normally

3. The only problem I see is that you void the warranty on the system. Why not just use the complete Laticrete system if you feel the liquid will be easier for you to use? If you decide to do both, I would put Kerdi band where floor meets wall, then run hydroban to overlap it coming down the wall.

4. Hardiback does tend to suck the moisture out. You can wet it down with a sponge first which will both clean it and moisten it. Im not sure why you would have Hardibacker under the tray or under Ditra though, theres no need.
MA/NH Home Remodeling
Executive Flooring is offline   Reply With Quote
Old 03-31-2013, 07:38 AM   #3
Registered User
Join Date: Mar 2013
Posts: 2
Hi Ray:

Thanks again for your advice. It's much appreciated.

With regard to the use of Kerdi and Laticrete, actually that was my plan, ie, to use Kerdi on the floor with the pan and around the sides of the pan and then use laticrete from there up. I thought about using laticrete all around, but I wasn't sure how well the Kerdi pan would accept the laticrete. There's also the warranty issues. I figured if I used Kerdi on the floor. If something happens there, the warranty might still hold.

I was thinking of using HardieBacker under the Kerdi tray simply to improve the adhesion of the thinset to the Kerdi tray. My understanding is that there were some issues with thinset adhering to the plywood subfloor, although I did see the Kerdi demo video where they did this. If you think it's OK, then I will probably skip that step. Likewise, I take it I can go directly from plywood to Ditra? Part of my thinking was not only adhesion but I was going to use the Hardieboard to raise the height of the floor by a 1/4 inch, so that the bathroom floor would be flush with the adjoining floor.


cjzullo is offline   Reply With Quote
Old 03-31-2013, 08:17 AM   #4
Join Date: Feb 2013
Location: Ancaster Ontario
Posts: 315
Hi. The Kerdi membrane is not difficult to do if you take your time and practise a bit before you start for real. If you are competent with a drywall knife and use the proper materials and tools, you should not be inhibited.
You can cut the kerdi into manageable pieces and overlap them if you need to rather than trying to do a piece 8' high.
jim_c is offline   Reply With Quote
Old 03-31-2013, 08:22 AM   #5
Join Date: Dec 2008
Location: Atlanta
Posts: 1,352
Laticrete also has premade pans and drains. So you can choose one system or the other and get the full warranty.
I personally prefer laticrete. Mainly because I get to use modified thin set.
Cain Curtis
A Tile Experience
Certified Tile Installer #362
Serving the metro Atlanta area

Cain is offline   Reply With Quote
Old 03-31-2013, 09:15 AM   #6
Steve C
Registered User
Steve C's Avatar
Join Date: Mar 2004
Location: Southern Illinois
Posts: 1,153
I've used the Kerdi tray, but I had several compelling (at least in my mind) reasons. I was able to build the shower around the tray; it was in a second floor bath suite, I did it by myself, and I didn't want to lug that much mud upstairs; it was 71" x 71" so I cut 1" off each of the 4 sides; the shower had limited headroom and it kept the shower floor height down.

I've also built and Kerdi'd a mud pan, and given all the details you've mentioned I'd encourage you to do the same. The advantages would be:

*You can fit it exactly into your space without compromising, and the drain can be anywhere you want it. I'd still recommend the Kerdi drain.

*Since you're looking for a little extra height, you can get that too.

*You'll save quite a few bucks.

You can find pretty much all the info you'll need in the Liberry. Don't let mud intimidate you. It ain't hard, or expensive.
Steve C is offline   Reply With Quote

Stonetooling.com   Tile-Assn.com   National Gypsum Permabase

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Kerdi installation pre-formed shower pan (not Kerdi Pan) mmerklin2002 Tile Forum/Advice Board 25 11-05-2012 07:59 AM
can i install a new pre-fab shower pan in an existing old mortar pan? tluns810 Tile Forum/Advice Board 9 05-12-2010 07:57 AM
how to install a shower seat when using a kerdi presloped pan? Clinton Tile Forum/Advice Board 6 05-14-2008 07:04 AM
First Shower Pan Install mbond Tile Forum/Advice Board 6 04-29-2006 04:56 AM
Shower Pan Install DougFordon Tile Forum/Advice Board 7 12-24-2002 09:12 AM

All times are GMT -6. The time now is 01:26 PM.


Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2014 John Bridge & Associates, LLC