Shed foundation - slab vs. pier questions

[knight82]

I plan on building a 10x16 shed on a slightly sloped area (maybe off less than a foot from one end to the other). I want to do most if not all of the work myself if possible. However, I am having a large section of my concrete driveway re-poured in the near future so I though perhaps combining the two jobs might save some time or $$.

I want to secure the shed to the ground (high winds) so originally I thought about using concrete piers, attaching 6x6 treated skids (lumber) to the piers and building the wood floor on that. I'm not sure though how many piers (3piers x 2rows) or (3piers x 3rows) etc to use, or what diameter 8", 10", etc or if I needed rebar inside the piers?

Since the driveway will require a large delivery of concrete, I was wondering if perhaps the floating slab might be a better option? If I did the prep work then only the additional concrete is the cost. But I've never done a slab and I would want a smooth floor finish similar to my garage floor. So there would be perhaps some cost for the finish work as well. Is there more or less prep work for this method? (leveling the ground, more digging, vapor barrier, etc) . Any ideas what is the better long-term solution? Cost differences, opinions?

I'm good with the carpentry but new to concrete. I looked at the cost of the wood just for the flooring and I thought perhaps the slab might be more cost effective? Piers and wood floor allow air circulation though.

[Rich]

I would personally go for the concrete slab with either a foundation, thickened edge, or piers. The system you choose might better be left to the concrete placers - as they'll know what the "norm" is in your area.
If you go with piers I would suggest a 10" diameter with 4-#4 rebar vertically - with 3" of concrete cover on top and bottom - 2" from the sides.

[mjpliv]

Which ever foundation you choose, if you are concerned about the wind, design your uplift restraints from the concrete through to the rood structure. Plan ahead. Make sure you have a method to anchor the assemby to the concrete.

If you are talking about more than one truck load of cement pour the shed first (hopefully it is the farthest away) and try to time the rest so that the slab will be stiff enough to power trowell when the last of the concrete has been bull floated and edged. That way the concrete contractor doesn't have to send a crew back. The concrete should be stiff enough to walk on and have no visible standing water.