Well we'd like to put in a 350 sq ft deck and since the slab is within
an inch or two of the interior floor it doesn't allow us to put joists
over the top of it.

I'm pretty sure that code prevents us from actually fastening the deck
support to the slab (as it's not structural).

The only other option (that I can see) would be to nail 2x4's flat onto
the slab and lay the decking boards on the 2x4's. The rest of the deck
support would end up being freestanding on concrete piers and perhaps
attached to the house in a few places. Unfortunately since the slab is
split clean in two, i'm worried that it could move apart and warp the
deck.

Graham