Flooring Tile - Acceptable conditions for natural stone?

I'm trying to figure out what to do with a second floor master bathroom. It is 10'x13', with the long side being an exterior wall and the joists running 10' + an additional 5' into another room.

2x10, 12" OC
Unsupported span = 15'
I am only looking to tile 10' of the 15'

Sub floor is 1/2" ply with 5/8" ply underlayment, all glued and screwed with offset joints.

I'm guessing the span is not going to be stiff enough to handle natural stone. The alternative is to tile the shower and lay hardwood in the rest (not too concerned about moisture given the way I plan on building the shower).

Sistering joists is out of the question because of the span and amount of plumbing running through that area. Any other ideas?

Thanks!

Damon

According to your description of the support structure, I'm not so sure but what you might be OK. I'm not that well versed on this though, so I'd suggest waiting for a reply from someone who is.

Hi Damon,

Your hunch was right, that floor is not sturdi enough for natural stone. You should be fine for ceramic or porcelain though. Those joists are overspanned for stone, builders do not build floors for stone tiles, they only do the minimum they can get away with. The basic maximum deflection for residential is usually L360, I think your floor is about L420 if everything is in good shape. The maximum deflection for stone is L720.

I definitely would not recommend hardwood in a full bath. And...neither would any wood manufacturer that I've heard of.

Jaz