Ceramic over 1" plywood


Old 07-05-07, 11:20 AM
Thread Starter
Join Date: Jul 2007
Posts: 1
Received 0 Votes on 0 Posts
Ceramic over 1" plywood

Forgive me if this has been answered elsewhere.

I have a new 1" plywood subfloor in a very small bathroom (4x* to be tiled) - Do I need a concete board on top of this? Will anthing else suffice?

Thanks, in advance, for any and all advice!
Sponsored Links
Old 07-05-07, 06:01 PM
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
In order to answer this, you need to know the reason for the concrete board, then you can make your own decision. Tile and wood have dramatically different expansion and contraction rates. Consequently, it's not a good idea to lay tile straight to wood because, most of the time, it won't stay adhered. I have seen rare instances where it did, but in twenty years laying flooring, I can count those on one hand. Most of the repairs I've had to do have been due to doing this. The purpose of the concrete board is to compensate for that difference. The concrete board expands and contracts at the same rate the tile and setting materials do. The board, over time, may break loose from the floor in what's referred to as an uncoupling action, but the tile and board will not break loose from each other so the tile job stays together. There are three products I'm aware of that are generally approved for this purpose, concrete board such as wonder board or durrock, hardi backer, or schluter's ditra uncoupling membrane. The first two products come in either 1/4 inch or half. The half is for walls and the 1/4 is for floors. The CBU does not add any strength to the floor, consequently, there's no real reason to use half inch on the floor. It will cause height issues with your other flooring. The only real reason to use it would be if you do have height issues you need to address and a thicker material is needed. The thinnest of the three is the ditra membrane and would be the way to go if height is an issue. There are those on this site who claim it's the only way to go regardless and they may well be right, but I have no hands on experience with it. My personal preference is the wonder board or durrock.
Old 07-05-07, 08:32 PM
Join Date: May 2007
Location: USA
Posts: 1,607
Received 0 Votes on 0 Posts
You do not want to install tile directly to plywood, and that goes double in rooms such as a bathroom.

I believe Ditra is the best way to install tiles to a floor, however, for a small job like this you're better off (financially) to just use a CBU. Make sure not to forget the thinset mortar under it too.

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: