Durock

[Caldwell]

Should I install 1/4" Durock over OSB if I plan on installing 13 X 13 porcelain tile on my bathroom floor?

 

[fire245]

Should I install 1/4" Durock over OSB if I plan on installing 13 X 13 porcelain tile on my bathroom floor?

Yes, screw off the osb first every 4 to 6" or so. Then durock over. Use a polymer based thin set.

 

[mopar440_6]

I prefer Ditra or a similar waterproof membrane underlayment for bathrooms. Helps protect the OSB from any moisture that leeches through the grout and its a heck of a lot easier to work with than cement board.

http://www.homedepot.com/p/Schluter...n-Thick-Uncoupling-Membrane-DITRA5M/100143471

 

[Highbeam]

Should I install 1/4" Durock over OSB if I plan on installing 13 X 13 porcelain tile on my bathroom floor?

That's what I do.

 

[semipro]

I've done it both ways with success.
I think if I was to do it again I'd put down the backer board and then coat it with Redgard, then lay the tile. This should give you the added stiffness of the backer board with the waterproofing and isolation of Redgard.

 

[bobdog2o02]

I've done it both ways with success.
I think if I was to do it again I'd put down the backer board and then coat it with Redgard, then lay the tile. This should give you the added stiffness of the backer board with the waterproofing and isolation of Redgard.

As a contractor this is what i do in wet areas. I prefer hardi backer over durock for ease of cutting. I have a circular saw blade and table saw blade just for with hardibacker.

 

[Dune]

Thing is the tile association wants a minimum of 3/4" plywood under tiles, How does 5/8" OSB compare in stiffness? I am guessing not well. This can result in loose tiles, broken tiles and cracked grout seems. Just sayin.

 

[Highbeam]

Thing is the tile association wants a minimum of 3/4" plywood under tiles, How does 5/8" OSB compare in stiffness? I am guessing not well. This can result in loose tiles, broken tiles and cracked grout seems. Just sayin.

All we know is tile over OSB. He didn't say anything about the thickness or support of the OSB.

 

[Dune]

All we know is tile over OSB. He didn't say anything about the thickness or support of the OSB.

Agreed. Standard subfloor is 5/8 and in my estimation, OSB is not as stiff as plywood, but I don't know that for sure.

 

[ironpony]

standard here is 3/4 osb t&g and depending on manufacture can be much stiffer. also depends on floor joist framing, spacing and type, white wood, southern yellow pine, trusses, tgi. spacing 16 inch 19.2 or 24 on center. When I was on the east coast standard drywall was 3/8, moved here everything is 1/2. We need to be careful what assumptions we make. We are scattered all over the country.

 

[semipro]

I prefer hardi backer over durock for ease of cutting

Same here.
However, I've seen some reports lately of rotting Hardibacker in wet areas like showers. I'm not sure how accurate they are but it does make some sense since I believe Hardibacker contains wood fibers where Durock doesn't.
Anyway, on my last shower job I used Durock with Redgard over it.

 

[Highbeam]

Same here.
However, I've seen some reports lately of rotting Hardibacker in wet areas like showers. I'm not sure how accurate they are but it does make some sense since I believe Hardibacker contains wood fibers where Durock doesn't.
Anyway, on my last shower job I used Durock with Redgard over it.

The durock has a label that says no wood or gypsum ingredients. It is a bugger to cut though. Not the straight cuts but things like notches around door jambs.

 

[bobdog2o02]

Hard I makes a backer "for wet locations" idk but I'd bet some hack installed the 1/4" stuff where it doesn't belong.