# 1/2" or 1/4" Durock Cement Board?



## HanDIY (Jul 18, 2009)

I am currently getting ready to lay my cement board down (Durock) in the bathroom floor that I am remodeling. I was trying to save some time and not remove my door frames and just tile/cement board under them. However, on one side there is plent of room for me to use 1/2" Durock and tile, while on the other side it is a tight fit and I will most likley have to "squeeze" in the tile/cement board combined thickness. My question is, is it ok to use 1/4" Durock on the floor under my tile or do I have to use 1/2" Thanks for the help


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## Bud Cline (Mar 12, 2006)

Durock 1/4" is made for floors. Either can be used on floors but only 1/2" can be used on walls.

Don't forget you *MUST install the cement board in a bed of fresh thinset* - ALL manufacturers require it.

You should also be undercutting you jambs and casings to accept the tuck of the cement board and the tile *AND *the two layers of thinset it will take to install all that stuff.

Undercut saws are cheap and can be found at all home centers.

Squeezing and forcing and pinching tiles will only lead to broken tiles in a short time. :yes:


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## HanDIY (Jul 18, 2009)

Bud, thanks for the quick reply. Great information, I will be returning the 1/2" to Lowes!:thumbup:


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## Bud Cline (Mar 12, 2006)

To save a few dollars you can use unmodified thinset ($5-$8) under the cement board.


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## HighlanderShawn (May 11, 2018)

Bud Cline said:


> Durock 1/4" is made for floors. Either can be used on floors but only 1/2" can be used on walls.
> 
> Don't forget you *MUST install the cement board in a bed of fresh thinset* - ALL manufacturers require it.
> 
> ...


What if you have an older house with 1/2" solid wood boards laid diagonally for the subfloor? How do you keep the thinset from running through the gaps?


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## chandler48 (Jun 5, 2017)

1/2" of anything isn't enough support for tile. You probably have 3/4" diagonal planks and will need an additional 1/2" to fortify the floor so the tile won't have cracking problems. What is your joist size and spacing and the longest unsupported span in the room?


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