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

Sponsors


Reply
Thread Tools Search this Thread
Unread 07-24-2021, 07:15 AM   #1
ohliuw
Registered User
 
Join Date: Nov 2013
Location: Ottawa
Posts: 46
CBP unmodified thinset and Kerdi

My first time doing kerdi shower base. I usually use the LFT CBP thinset with large tiles, but I followed the Kerdi instructions to use unmodified.
I usually mix the mortar the way I like to work with, but this time I decided to follow the instructions on the bag, which said 5.7 litres per bag.

I am not sure if there is a typo, but I could not even mix it properly - my drill wouldn’t even spin - so I added extra 0.5 litres and managed to somehow mix it. It ended up very hard to work with, I was barely able to set the shower pan and to install the Kerdi corners, then had to throw out the rest (I was planning to lay the tiles at the same time, which obviously didn’t happen). So my 2 questions are:

1. Why the recommended ratio didn’t work for me? Should I go by feeling when I lay the floor tiles?

2. Kerdi says to use unmodified thinset, but on the curb and on the walls at the bottom where I have the Kerdi band I need to use 4x24 tiles, and the unmodified thinset is only good til 15”, so what thinset I use for those?

Thanks
__________________
Cleo
ohliuw is offline   Reply With Quote
Sponsored Links
Unread 07-24-2021, 07:57 AM   #2
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 93,620
What unmodified thinset mortar from Custom did you use, Cleo?
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 07-24-2021, 08:00 AM   #3
Lazarus
Texas Tile Contractor
 
Lazarus's Avatar
 
Join Date: Oct 2006
Location: Beaumont, Texas
Posts: 8,450
Probably Customblend. Only unmodified they generally stock. Worst stuff I've ever seen...

Mapai makes a good, unmodified morter.
__________________
Laz
Lazarus is online now   Reply With Quote
Unread 07-24-2021, 08:31 AM   #4
ohliuw
Registered User
 
Join Date: Nov 2013
Location: Ottawa
Posts: 46
This one:

https://www.homedepot.ca/product/cus...-kg/1000173400
__________________
Cleo
ohliuw is offline   Reply With Quote
Unread 07-24-2021, 08:50 AM   #5
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 93,620
That mortar is no longer available south of the 39th parallel, Cleo. When it was available, it was the only useful unmodified mortar in the Custom line. Not great, perhaps, but usable.

There have been times when we've found serious discrepancies in the printed instructions on the bags of thinset mortars, particularly in the amount of water required. I cannot say that's what you're dealing with there, but you might check the bag instructions against the most current online published specs.

There are thinset mortars that require more mixing time than you would expect and those times are in the instructions. That should not be the case with an unmodified mortar, though, unless I'm seriously out of touch.

We (TYW) strongly recommend reading and following manufacturer's installation instructions, but there are times when it makes sense to deviate from those instructions a bit. Schluter's requirement for unmodified mortars for use with their membranes is one such time in my opinion. Custom's VersaBond works quite well with Schluter's membranes and any other similar membranes. Indeed, all other membrane manufactures require the use of a modified mortar meeting ANSI A118.4 (check your ISO equivalent).

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 07-24-2021, 10:38 AM   #6
ohliuw
Registered User
 
Join Date: Nov 2013
Location: Ottawa
Posts: 46
Thanks, will use Versabond for the tiling. I hope the base and the membrane will be ok with the one I used.
__________________
Cleo
ohliuw is offline   Reply With Quote
Unread 07-24-2021, 10:42 AM   #7
Tool Guy - Kg
Moderator -- Wisconsin Kitchen & Bath Remodeler
 
Tool Guy - Kg's Avatar
 
Join Date: Feb 2005
Location: Oak Creek, WI
Posts: 22,844
Are you going to perform a flood test before tiling?

__________________
Tonto Goldstein... but my friends call me Bubba

Help an awesome summer camp!
Tool Guy - Kg is offline   Reply With Quote
Unread 07-24-2021, 01:42 PM   #8
jadnashua
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

 
Join Date: Jul 2004
Location: Nashua, NH
Posts: 14,501
Mixing thinset needs to do several things:
- evenly wet all of the components
- help to break up any smaller particles so it's smoother.

SO, while evenly wetting all of the components in a modified is critical, it can really help even with an unmodified.

FWIW, you need a fairly hefty drill motor to mix a full bag of thinset, regardless of the type. It's important to use the recommended speed, and many smaller drill motors can't turn at those speeds if the load it too high.

If you want a really good example of how mixing time makes a huge difference, try Latticrete's one with some pulverized rubber in it (helps with sound attenuation)...it looks like it will never come together, and then, poof, magic, all of a sudden, it's nice and smooth. Messes it up if you add extra water at the beginning because you think it's too dry.
__________________
Jim DeBruycker
Not a pro, multiple Schluter Workshops (Schluterville and 2013 and 2014 at Schluter Headquarters), Mapei Training 2014, Laticrete Workshop 2014, Custom Building Products Workshop 2015, and Longtime Forum Participant.
jadnashua is online now   Reply With Quote
Reply

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
Used regular unmodified mortar not thinset on kerdi TCS Tile Forum/Advice Board 9 05-06-2019 02:16 PM
kerdi and unmodified thinset danxp Tile Forum/Advice Board 7 11-10-2012 08:49 AM
Kerdi, unmodified thinset and Water pwa Tile Forum/Advice Board 6 07-20-2008 08:46 AM
Thinset for Kerdi, modified or unmodified? jalge2 Tile Forum/Advice Board 6 05-19-2008 11:12 AM
kerdi shower - unmodified thinset both layers? thenewguy Tile Forum/Advice Board 6 05-28-2006 08:06 PM


All times are GMT -6. The time now is 08:35 PM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC