Subfloor under Ditra question

Reply

  #1  
Old 06-28-09, 11:10 AM
Member
Thread Starter
Join Date: May 2009
Location: North Carolina
Posts: 11
Received 0 Votes on 0 Posts
Subfloor under Ditra question

Hi there-
I have a few questions about subfloor prep for ditra installation.
Subfloor is 5/8" plywood with 1/4" osb over top, previous owner had linoleum floors. I am removing the paper backing and glue that stuck to the floor after pulling up old linoleum (nightmare, tedious job!). Using a steamer and putty knife to scrape up. I still have a bunch of places that I'm working on that have old glue, trying to decide how important it is that I get ALL of it up. I'll be using a modified thinset over subfloor to adhere DITRA.

From scraping (as gently as I could), there are many areas that the OSB has fine "hairs" of wood sticking up.

1. Am I ok with the 5/8" plywood and 1/4" OSB for ditra install?
2. Will those wood hairs cause any problems?
3. Will the modified thinset/ditra adhere properly to any areas that still have glue?
4. If I'm going to use a self-leveling compound in a few areas, will the thinset/Ditra adhere properly?

Thanks,
Brent
Charlotte, NC
 
Sponsored Links
  #2  
Old 06-28-09, 03:39 PM
HotxxxxxxxOKC's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2006
Location: USA
Posts: 8,044
Received 0 Votes on 0 Posts
1. Nope. You need to pull up the 1/4" underlayment too.

2, 3. My answer to #1 should fix that.

4. No problems.

Can I ask what your floor joists sizes (2x?), joist spacing (center 2 center), and the unsupported span of those joists?
 
  #3  
Old 06-29-09, 04:04 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
Remove the 1/4" underlayment.

Ditra over 5/8" plywood is a bare bones minimum installation. Consider adding more plywood, minimum 3/8", thicker would be better. Then install ditra.

Is the subfloor square edge plywood or t&g? If its square edge and you decide to install ditra over it, you'll need to add blocking under the plywood edges to fully support the seams between the joists.

Any leveling/flattening of the floor should be done under the ditra, not over it.
 
Reply

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:
Description:
Your question will be posted in: