CBU Expansion Joints [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-15-2003, 02:53 PM
Thanks for all the answers last week. In the past four days I've removed all the old vinyl flooring and adhesive off the plywood subfloor. I've placed all the CBU (Hardibacker) with 1/8" expansion gaps between each and 1/4" at walls and cabinets. Started fastening the CBU in thinset with approved screws. I must have been wandering out a little per board and there are a few gaps that are between 1/4" to 1/2". Is there something I can do to correct this before I fill with thinset and tape? The tiles will be 13" X 13" so I can layout the tiles and straddle these spots.
Thanks, Rich

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01-15-2003, 08:23 PM
You could tape and float the joints with latex mod. thinset just as you would an 1/8" gap or you could mix up some SLC and fill the joint...or I'm sure others will have some ideas.

In any case, as long as the floor is solid and there is no flex, the risk is low ( if not zero).

I've had a few cases where uneven cuts on the CBU have yielded wider than 1/8" joints. I taped, floated, and tiled over them with no problems


01-16-2003, 07:34 AM
Thanks Jason, I will do just that. The floor sure IS solid. It feels like you could drive a tank on it.

01-16-2003, 07:47 AM
Dont do it!!!!!!! Then Tanks are reallyyyyyyy Heavy!!!!!! :D
You will exceed your load rating!!:rofl:

01-17-2003, 07:55 AM
not to mention what it will do to those door headers :D