Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Flooring > Tiling, ceramics, marble

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-10-2013, 12:13 AM   #1
Member
 
Join Date: May 2010
Location: Los Angeles County
Posts: 204
Rewards Points: 150
Default

6 mil plastic on plywood?


1/4" backer board on 1/2" plywood attached to studs.

Do I need to install a layer of 6 mil plastic (aka vapor barrier) in between or is that a bad idea? I heard some people say it is actually not a good idea because it would create a mold sandwich between the backer board and plastic.

What are your thoughts?

jackwashere is offline   Reply With Quote
Old 11-10-2013, 05:24 AM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,005
Rewards Points: 3,126
Default

6 mil plastic on plywood?


What is this? A wall, floor?
What room is it in?
Inside, outside?

__________________
When posting in forums, letting us know your location will help others give better feedback/advice/solutions to your questions
joecaption is online now   Reply With Quote
Old 11-10-2013, 09:45 PM   #3
Tileguy
 
JazMan's Avatar
 
Join Date: Feb 2007
Location: Troy, Michigan
Posts: 4,071
Rewards Points: 2,000
Default

6 mil plastic on plywood?


It's a very bad idea regardless what it is. But please let us know what you're trying to do and we can set you in the right direction.

Jaz
__________________
Tile 4 You LLC Troy, MI

DITRA Installs - KERDI Watertight-Mold-Free Showers. I have NEVER made a mistake, I thought I did ONCE, but, I was WRONG! A+ BBB rating - est. 1987 - over 50 yrs. exp.
JazMan is offline   Reply With Quote
Old 11-10-2013, 10:47 PM   #4
Member
 
Join Date: May 2010
Location: Los Angeles County
Posts: 204
Rewards Points: 150
Default

6 mil plastic on plywood?


Quote:
Originally Posted by joecaption View Post
What is this? A wall, floor?
What room is it in?
Inside, outside?
Bathroom inside. Wall. I am going to tile the bathtub/shower and half a wall behind toilet and sink. I installed 1/2" plywood on the studs. Plan to install Hardie Backer on top of that. Should I install a 6 mil plastic in between the plywood and backer board or not?
jackwashere is offline   Reply With Quote
Old 11-10-2013, 11:39 PM   #5
Tileguy
 
JazMan's Avatar
 
Join Date: Feb 2007
Location: Troy, Michigan
Posts: 4,071
Rewards Points: 2,000
Default

6 mil plastic on plywood?


Okay, I'm gonna pretend you didn't see my answer.

Plywood in a damp wall area is not a good plan, but if it's done, well...........?

Never put plastic between boards. The vapor retarder should have been installed on the studs already. But the best waterproofing is surface applied, such as Kerdi membrane or a liquid membrane such as Redgard or Hydroban.

Which Hardie will you be using? Hardie 500 I hope.

Jaz
__________________
Tile 4 You LLC Troy, MI

DITRA Installs - KERDI Watertight-Mold-Free Showers. I have NEVER made a mistake, I thought I did ONCE, but, I was WRONG! A+ BBB rating - est. 1987 - over 50 yrs. exp.
JazMan is offline   Reply With Quote
Old 11-11-2013, 08:20 AM   #6
Bill Kearney
 
Join Date: Apr 2009
Location: Bethesda, MD USA
Posts: 1,922
Rewards Points: 1,006
Default

6 mil plastic on plywood?


Right, I would not have put plywood on the walls under the backer.

As Jaz suggests, it'd be better to put a waterproofing membrane on the backer and not use any poly at all. I've used Redgard and it works well. Yes, you paint it onto the backer and then apply thinset and tiles to it. Yes, it does hold, QUITE well. The upside is you can make a perfectly sealed wall. It costs more than plastic, but it's worth it.
wkearney99 is offline   Reply With Quote
Old 11-11-2013, 12:19 PM   #7
Tileguy
 
JazMan's Avatar
 
Join Date: Feb 2007
Location: Troy, Michigan
Posts: 4,071
Rewards Points: 2,000
Default

6 mil plastic on plywood?


I don't like the use of poly or even tarpaper on the studs under backer at all. It's a very confusing application that has lots of "ifs" and other conditions. The rules change according to location within the house and geographically.

Plus a vapor retarder on the studs is NOT a vapor barrier and is definitely NOT waterproofing. Waterproofing a wall is done with surface membranes properly applied.

Speaking of "properly applied". Many people, (including many pros), do not use liquid membranes correctly, they do not apply enough film thickness. Be sure to read the directions for the requirements. Liquid membranes such as Redgard and Hydroban require at least 2 coats and possibly 3. You should get a wet-film gauge to measure as you apply it. It's a very simple tool.

http://laticrete.blogspot.com/2011/0...ilm-gauge.html


Jaz

__________________
Tile 4 You LLC Troy, MI

DITRA Installs - KERDI Watertight-Mold-Free Showers. I have NEVER made a mistake, I thought I did ONCE, but, I was WRONG! A+ BBB rating - est. 1987 - over 50 yrs. exp.
JazMan is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Redgard vs 6mil Plastic Sheeting for tiling amodoko Remodeling 0 01-17-2012 11:57 PM
Staples or screws on plywood subfloor? And other questions.... howdihi Flooring 1 08-18-2011 08:50 PM
Roofing plywood advice needed jimd206 Roofing/Siding 2 04-24-2011 11:58 PM
Can you snake plastic pipes? rosemonster Plumbing 10 01-17-2011 07:09 AM
Removing tile from plywood underlayment Martinglmt Flooring 3 12-13-2008 07:06 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.