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
Unread 05-13-2021, 07:37 AM   #16
ss3964spd's Avatar
Join Date: Jul 2005
Location: Fairfax, Va
Posts: 4,271
Send a message via Yahoo to ss3964spd
Instead of 3/4" T&G OSB, with 3/8" ply on top you might consider 5/8" T&G OSB/ply with 1/2" ply on top.

3/8" ply isn't so great. The sheets typically are not very flat right off the rack, making them a bit of a challenge to get to lay flat on the floor. At least one of our members reported that his 3/8" ply bulged between rows of fasteners.

In any case, you'll want any ply you install to have a face grade of no lower than C, and rated Exposure 1/EXP1 - meaning the ply was made using a moisture resistant glue. You will want your first layer of ply/OSB glued and screwed to the joists, but your second layer screwed into the first layer of ply, with no adhesive between the two (unless yo intent to roll on a full coverage adhesive). See this article from our library for more detail. https://www.johnbridge.com/images/mi...-0604.pdf..pdf
If I recall correctly my memory is excellent, but my ability to access it is intermittent.
ss3964spd is offline   Reply With Quote
Unread 05-13-2021, 08:16 PM   #17
Registered User
Join Date: May 2021
Location: Portland, Oregon
Posts: 10
Which thinset for CBU to OSB?

Hi all,
Wondering your thoughts on which thinset to put under cbu to 3/4 osb subflooring.
Normally I use a modified. But have heard some recommend un-modified?

And lastly, if I was to do a second layer of plywood for height (if needed) before cbu, would you guys recommend troweling titebond2 for the ply to osb bond? Maybe scuff the osb to help with glue?

Davidjames1 is offline   Reply With Quote
Unread 05-13-2021, 09:46 PM   #18
Moderator emeritus
cx's Avatar
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,958
David, it'll help if you'll keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered.

You want to go to the CBU manufacturer's website and look at his installation instructions. That will include the type of mortar to be used under the CBU panels. It's usually either modified or un-modified, but some specify modified. I don't know why. The purpose of the mortar is to provide a 100 percent footprint for the CBU panels, not to bond it to anything. The mortar holds the panel up, the mechanical fasteners hold it down.

I've always been a big fan of gluing all parts of a wood framed subfloor, but I wouldn't try gluing anything to OSB. If you follow the instructions from this good article from our Liberry, you'll be fine.

My opinion; worth price charged.

cx is offline   Reply With Quote
Unread 05-14-2021, 01:14 AM   #19
Registered User
Join Date: May 2021
Location: Portland, Oregon
Posts: 10
Thanks for the reply guys!

At my big box store they have ACX 1/2” and 3/8. It’s clean considering what I have seen at our stores in previous years.

I will know by today if 1/2” will work over the osb once demo is done.
Davidjames1 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
Porcelain tile in a kitchen, plank subfloor. Cordate Tile Forum/Advice Board 4 01-20-2018 01:06 PM
How to Install Porcelain Tile over Plank Subfloor. Please help! thull Tile Forum/Advice Board 6 07-14-2017 12:14 PM
Ceramic Tile on Plank Subfloor? ttown419 Tile Forum/Advice Board 5 02-21-2013 07:10 PM
Tile over plank subfloor (again) stevemar Tile Forum/Advice Board 14 06-21-2011 10:25 AM
How do I tile over a plank subfloor? fishin49 Tile Forum/Advice Board 2 01-22-2007 03:26 PM

All times are GMT -6. The time now is 08:46 PM.


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