On Mar 2, 6:02 pm, wrote:
"I'm confused, if the pool is 16 ft wide...why would the span be 18
ft?"

The joists would have to be larger than the pool itself, no? I was
thinking that they would need to extend about a foot or so on either
side of the pool. How else could it be done?

Frank-

This is why you need a design / construction pro....the definition of
"span" is the clear distance between supports. Hence the term "clear
span".

The fact that you have been concerned about the pool supporting the
deck load plus thinking that the joists extending beyond the edge of
the pool also extends the "span" tells me that you are in over your
depth...get in touch with someone local) who can do this design for
you.

This isn't the space shuttle....its just a deck over a pool.

cheers
Bob