Latest Discussions : Flooring & Stairs


07:52PM | 01/02/08
Member Since: 01/02/08
1 lifetime posts
I'm about to do a tile job and thought I had all the answers... then I saw that there are some brands of cement board that ask to be mortared AND screwed down on top of the subfloor. I was planning on getting 1/2" cement board and screwing it down, then tiling on top. I did some measurements and this would be the perfect height to match up with the new hardwood floors I just put in. If I need to put mortar down first, I'm wondering if I'll have to go to 1/4" cement board since all the mortar (on top and bottom) will significantly change the thickness of my floor.

When I researched this on the net, I found that several people suggest to use the mortar and screws method, however, in my laundry room I wanted to go with 1/2" cement board since I have a front load washer that shakes rather voilently when in rinse mode. I was hoping that the thicker cement board would create a firmer floor to prevent any chance of cracking the tile.

So there you have it. Should I go with 1/2" cement board and just screw it down? Or should I go with 1/4 cement board and mortar and screw it down, then build up to match the height with my hardwood?

doug seibert

03:25AM | 01/03/08
Member Since: 08/10/02
842 lifetime posts
From James Hardie:

....Floor Installation.......We recommend 1/4" HardieBackerâ„¢ board for floor applications,

unless 1/2" thickness is needed for transition............ Attach HardieBackerâ„¢ cement board to subfloor

........Apply a supporting bed of mortar or modified thinset to subfloor using a 1/4" square-notched trowel

.........Embed HardieBacker cement board firmly and evenly in the wet mortar.

USG Durock underlayment....Installation PDF:

Underlayment is 5/16" and is required to be installed in a bed of thinset/mortar......

Custom Building Products WonderBoard:〈=en

From the installation PDF〈=en

........1/4" or 1/2" installed in mortar or thinset

"...measure once.....cut twice....throw that one away and cut a new one...."


08:13PM | 01/03/08
Member Since: 08/29/07
56 lifetime posts
The thinset is necessary for filling in gaps on the floor so you end up with a firmer floor. It only adds a nominal amount that you won't even notice.

As far as the washer goes. Get it fixed. Sounds out of balance or something. Backerboard adds no strength to your floor.

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