Thanks! This is good information! I think I can be a bit more clear on the situation...
First, I am near Atlanta, GA - I am not sure how that affects frost/freezing requirements.
The sunroom is off the second floor with nothing under it except these poles holding it up, it also has an exterior door out to a deck with a staircase. The underneath is enclosed with lattice.
I have a picture of it, from another really exciting day of homeownership - I don't know if from this picture you can see the TREE Hurricane Dennis relocated clearly, but it is on the chimney! The deck and stairs have been replaced since this picture, and are anchored solidly in concrete.
This sunroom was built by the previous owner - and after repairing many of his "improvements" we long ago decided not to jump in the sunroom!! Pretty much just my cats enjoy it. I have always felt it had quite a slope, too, and figured it probably started out as a deck, sloped for drainage, and the sunroom was added onto the deck...
Anyway, I do appreciate the information.