Can I Use Thin Set Mortar Over Interior Grade Plywood? - Flooring - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Flooring


Thread Tools Display Modes
Old 02-19-2011, 04:56 PM   #1
Join Date: Feb 2011
Posts: 7
Rewards Points: 14

Can I use Thin Set Mortar over Interior Grade Plywood?

I am planning to add 1/4" cement board and tile to my subfloor. My subfloor consists of two layers of 1/2" to 5/8" plywood. The plywood was manufactured in 1983 and is marked C-D exposure 1, which I think means it is an interior grade plywood.

All the literature I read on applying thin-set is that it is only recommended for exterior plywood. I heard that applying wet thin set mortar over interior grade plywood could cause plywood delamination.

Should I paint or possibly seal the plywood surface with something first or just apply the thin set mortar down directly over the plywood and don't worry about it?

Also the plywood is very tight fitting with no gaps between sheets. Is that ok?



Last edited by JFERTICH; 02-19-2011 at 05:06 PM. Reason: added info for clarity
JFERTICH is offline   Reply With Quote
Old 02-19-2011, 05:08 PM   #2
DIY staff

Join Date: Sep 2009
Location: Kane county,Illinois
Posts: 25,728
Rewards Points: 2,174

Not a worry.

The thinset will not delaminate the ply----Go for it.

I've done this countless times without a problem.----Mike---


New members: Adding your location to your profile helps in many ways.--M--
oh'mike is offline   Reply With Quote

Thread Tools
Display Modes

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Thin set vs mesh porcelain floor tile over plywood subfloor and vinyl flooring Jerseygirl Tiling, ceramics, marble 49 05-23-2013 01:04 PM
coverin plastic tile wall with panelin or thin plywood. how to cover the seams? chinolofus Remodeling 2 11-23-2010 06:52 PM
Fixing a screwup - stain on oak plywood brich Carpentry 9 05-13-2010 11:09 PM
Basement Concrete Block Mortar Seepage Advice Nightcrawler Building & Construction 6 09-22-2009 08:57 PM
Mortar or thin set for brick pavers bdawson General DIY Discussions 0 04-27-2008 01:44 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1