Building a shed on concrete slab

by Gary

I want to build a shed (7' x 14') on an existing slab, which is somewhat larger than the shed will be. The slab is at the level of, or slightly below, the surrounding earth, and doesn't drain well. So I am thinking of building a raised wooden floor. My plan is to use 2x4' joists to keep the 'step up' minimal (several yard machines to roll in and out); they won't really be 'spanning' anything, but resting on the slab.

If I use pressure treated wood, can it just rest on the slab, which will sometimes have 1/4" of water on it, without any problems down the road? Or should it be isolated from the concrete with some sort of spacer?

First shed project for me; I'm sure it will be interesting.

Thanks...

Gary