Thanks a lot for all your feedbacks,
Looks like a beam and pier floor is possible if correctly supported. I also appreciate all the feedbacks about putting wood on top of a slab for older people :). In my case the issue is more about a slab not allowing storm water passing under and might require some costly retaining walls. A floor on pier and beam supported by pilling allow for water under. I am talking about hurricane type storm water, like a lot of water.
At least now I know I can do both.
Bill
