is this subfloor strong enough for ceramic tile ?

mf915

I currently have vinyl+luan on 3/4" OSB subfloor. I'd like to replace them with ceramic tiles. The joists are 2x10 (I-shape) and they're 24" apart. Below the kitchen and living room is the basement, which has metal support beams in the middle (12 feet for kitchen, 12 feet for living room). So the span of unsupported length is 12'.

I will try to remove vinyl+luan. Then, at the least, I know i need to add 1/2" OSB/plywood exterior grade and 1/4" Cement board.

Is this setup (2x10, 24" OC, 12' unsupported) strong enough for all these extra weight (i.e. ceramic tiles, plywood, cement board) ?

Thanks

Glasshousebltr

I'd say it's under suported as it stands. Min. for floor truss is 19 3/16 OC and floor truss have a 3 1/2 inch seat. However, Standard 10" I joists will span the 12', if on 16" oc. So, I'd say it's time to beef her up.

Not only that, the last thing ya want with the ceramic is a massive deflection. The popping grout will make ya wear safty glasses to cross it.

Bob

Bob

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glasshousebuilder.com

manhattan42

It is not possible to say if the engineered floor system is strong enough without knowing the manufacturer of the I joists, the depth of the I joist, the size of the I joist flange and so on.

Only way you will be able to determine this is to check the stamp on your joists and then look up their span characteristics on the manufacturer's website on in their printed literature.

Generally speaking, for structural sheathing, 3/4" OSB of plywood can span up to 24" between joists with a 10lb psf dead load and is likely at or beyond it's load bearing span limit for a main floor and would need additional reinforcement.

Nothing can be said about the ability of the I joists to bear the additional load without knowing the details about the joists and the type of tile you will be installing.

If you can't determine the load bearing from the product literature, contact your local code office and/or an architect/engineer.