Tile backer boards types and size

newgarage

I am going to install 12" ceramic tiles for my kitchen-dining room renovation. I have put down 3/4" cdx plywood over the existing 1/2" plywood on 2x10" 16"o.c. joists. Home Depot carries 1/2" and 1/4" wonderboard 3x5', 1/2" wonderboard 4x8', and Hardie 1/2" 3x5'. I was told Hardie is a fiber-cement board and wonderboard is cementious backer. What type, size, and thickness is best. My only experience in the past was 1/2" 3x5 durock for tile setting. Lowes carries permbase also 1/2" or 1/4" in 3x5 or 4x8'. Also 4x8' sheets would line up on joists underneath and straddle plywood seams evenly, but does this matter for tile backing? Should tile backer be laid down in a certain pattern over plywood as far as the seams go? Is taping and thinsetting seams necessary or can they be caulked?

angus242

Are you familiar with Ditra? That's the way I'd go.

Otherwise, CBU of your choice. Any CBU product in 1/4" will work fine. Use alkali resistant screws to attach, use alkali resistant tape and thinset over the seams.

Too late now but for anyone else reading this, TCA Handbook (tile bible) calls for exterior grade plywood, not CDX. The grain of the ply should run perpendicular to the joists. Do not align the CBU with the ply but stagger the CBU seams and leave 1/8" gap around perimeter.

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Angus

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newgarage

Thanks, I'm going to see if I can find that TCA handbook you referred to. A little extra info always helps.

angus242

The TCNA handbook is available for purchase via:
http://www.tileusa.com/publication_main.htm
You may want to wait for the 2009 version. As far as I know, it's not available via download anywhere. That might change for 2009???

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Angus

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