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 09-15-2018, 03:52 PM   #1
Registered User
Join Date: Jan 2017
Location: Philadelphia, PA
Posts: 3
Another CBU Wicking Question

Hello Everyone,

This is my first time asking for some advice after lurking in the shadows for a bit.

After researching the topic wicking with the CBU inside the mud bed, I still don't see a concise answer. Some answers say to embed it and others say to keep it slightly above the mud.

I was thinking of another option:

Has anyone tried RedGarding the bottom 8 inches or so of the CBU on all sides and once dried, THEN install it in the mud as recommended?

I don't see any negatives with pre-RedGarding and that might mitigate any wicking concerns.

Does anyone have any opinions on this?

Thanks for any input!

mis_desk is online now   Reply With Quote
Sponsored Links
Old 09-15-2018, 05:27 PM   #2
Da Home Builder
cx's Avatar
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 86,161
Welcome, MD.

From our Parent Site.

I would not recommend that. Fine to use your direct bonded waterproofing membrane on the face of your wallboard before you place your final mud bed, but don't put the membrane on the bottom edge of the board. Water will find its way into the CBU over time and it needs a way to exit at the bottom into the mud and finally to the drain.

My opinion; worth price charged.

cx is online now   Reply With Quote
Old 09-15-2018, 05:50 PM   #3
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

Join Date: Jul 2004
Location: Nashua, NH
Posts: 12,413
There are two different classes of cbu:
- fiber cement boards (such as HardieBacker)
- 'real' cement boards (most of the others, but not all)

The TCNA guidelines list two methods, one for each of the two classes of cbu. A fiber-cement board should NOT be embedded.
A 'real' cement board CAN be embedded.

Read and follow the instructions for the brand you choose to install.
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 offline   Reply With Quote
Old 09-15-2018, 08:23 PM   #4
Moderator -- Mud Man
Davy's Avatar
Join Date: Jan 2003
Location: Princeton,Tx.- Dallas area
Posts: 30,194
Yep, what the others said. If you cover the bottom 8 inches then moisture will soak in above the Redgard, gravity will pull it down and it'll be trapped. If you're going to cover the CBU, cover the whole wall on the tile side only.

Davy is offline   Reply With Quote
Old 09-16-2018, 06:55 AM   #5
Registered User
Join Date: Jan 2017
Location: Philadelphia, PA
Posts: 3
Thanks for all the input, it's much appreciated.
mis_desk is online now   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
So. Cal wicking Nailgun Tile Forum/Advice Board 37 02-07-2014 09:35 AM
Yet another Kerdi wicking question, Kuzimmer Tile Forum/Advice Board 5 01-24-2013 08:24 PM
Wicking tile cfonthehill Cleaning, Restoration and Sealing 4 06-29-2011 01:32 PM
wicking truman1313 Tile Forum/Advice Board 1 11-16-2004 10:31 AM
Wicking JC Professionals' Hangout 6 06-02-2003 10:12 PM

All times are GMT -6. The time now is 04:20 PM.


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