Subfloor Recommendation For Ceramic

72chevy4x4

I have a small bathroom, 4x6, which has a 3/4" subfloor (particle board). Before laying the cmu, should a 1/2" layer of plywood go down to build up to 5/4" ?

R&D Tile

Particle board or OSB?, if particle board, it has to come up.

MattCoops

It's probably most likely not particle board
you probably have chip board which some people call particle board for some reason

you can trowel thin-set and screw wonderboard over subfloor

and tile over that

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Matt with Cupan Custom Tile & Paint of Lowell, Massachusetts
Design and installation of ceramic tile and natural stone for floor, wall, and countertops
(978) 601-8774 | cupantile@gmail.com | view tile pictures and more

Gordo

I know you need at least 1"1/4 sub-floor before cmu. Plywood over OSB? I cannot say yes or no.

If it is real particle board like that stuff they put down in the 80's I'd tear it out...then go back with ply.

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Looks like some pros were here.

72chevy4x4

my bad, it is osb. I ended up putting down a layer of thinset, then screwing down duroc.

A side question concerning the tile work: because of the dimensions and variety of tile sizes, I made the joints going one direction slightly larger then the other direction (so as not to have a thin tile piece at the wall). The tiles ranged in size from 14" square, 7x14 and 7" square. Is there potential for failure in joints (cracking maybe) from being too large? The size wasn't riduculous-just 1/8" larger than what I had been using in the other direction.

reveivl

Sanded grout? How big are the joints?

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