On 2007-07-13, Art wrote:

So 7 inches of the tub is cantilevered, 6 inches are sitting on
joists directly above the sill plate (which is on a concrete
foundation wall), and 16 inches are on the other side of the sill
plate

I am not an engineer, but I would say that since your tub is less
sitting on top of a strong support (the concrete wall), the bending
moments induced in the 2x10 floor joists, even at 100 psf load, are
comparitively small. So there is certainly no need to strengthen the
floor system as far as bending of the joists goes; you should check
the bearing area to be sure the joists won't crush over the wall. It
would be a very different situation if you had your tub in the middle
of a 16' span, say.

Cheers, Wayne