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 02-24-2008, 08:19 PM   #1
Registered User
Join Date: Feb 2008
Location: nova scotia
Posts: 1
Cement Board

Hi " Just joined up and my first post. I have 7/8" OSB on the floor of my entry ( 70 SQ') and I am going to install porcelan tile. Under the OSB there is two layers of 1'' boards on 2X10 on 20 " centers. (Real old house) First I was going to install 1/2" cement board with unmodified thinset under and modified thinset over to install the tiles. Am I on the right line of thinking? Do I need expansion joints when I install the cement board? thanks
jjmacneil@ns.sympatico.ca is offline   Reply With Quote
Sponsored Links
Unread 02-24-2008, 08:24 PM   #2
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

Join Date: Jul 2004
Location: Nashua, NH
Posts: 13,335
Two things, unless you have a need for the height, you only need 1/4" cbu on the floor. Then, have you determined the joist deflection numbers? Use the "deflecto" in the blue bar above. Unsupported lengths are what's under the floor, not what is above the floor.

How long an area are you going to tile? That and whether it gets a lot of sun will determine if you need expansion joints.
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
Unread 02-24-2008, 08:30 PM   #3
Conceptsplus- Randy Gilmore
conceptsplus's Avatar
Join Date: Feb 2008
Location: Springfield, Mo
Posts: 419
That floor structure sounds questionable. I'd check deflection here.
Check the specs on the cbu you use and follow the installation guide for the spacing of the sheets. You also need to tape the seems on most of them, excluding wonderboard, I think. They have the tapeless installation. Unless they've changed that.
Randy Gilmore

Natural Stone Contractor - Springfield, Missouri
Website needs updates- be back soon.
conceptsplus 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

All times are GMT -6. The time now is 07:55 PM.


Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC