I haven't been to this group in awhile, so hello all.

I have a screened porch that is 14' x 14', and is surrounded by an uncovered
deck (Trex). The floor of the porch is (I'm pretty sure) tig fir, and the
wood itself seems in good shape.

I want to know if there's a material I can put over that floor, possibly
vinly, or anything else, for that matter. This is New England, so things
freeze in the winter, and screened porches get all the weather when the wind
blows. This home is 40 yrs old, and the hand-built screens themselves will
have to be replaced soon anyhow, so thickness of a new material isn't a real
concern. I would love to do tile or somthing like that, but there is a lot
of flex in the existing floor. I'm a lightweight, but I make things rattle
on the table just by walking out there, and heavier friends can actually
bounce things.
That I can live with, but my knees complain too much for me to paint floors
anymore, and this one needs it more and more often it seems.

Underneath there is varying space, probably 12" to 14", then earth
underneath. I would love to put down something substantial out there for a
floor (tile or Chicago brick), but being in New England that seems a bad
choice, given the freeze-thaw conditions in winter. I suppose I could
increase rigidity by cutting a few holes in the existing flooring and
installing some permanent jacks, but I'd like something simpler, even if
things do still bounce around.

Has anyone laid down vinyl flooring in a situation like this? Are there
composite boards that aren't made for decking, and therefore aren't an inch
thick? Can I get vinyl that's 14' wide and take my chances?