question for innerlooper

[GREASER]

I am going to build a storage building in the back yard at the site of the previous garage. There is a slab, but its cracked and just above grade level, and just barely. So question is, should I just go pier and beam on top of the slab, or is there a way to still use the slab? or at least get the lower sill boards off the ground (like using concrete pads). I have alot of heavy things that I would love to keep in there (engines for one) and cant roll around on peir and beam due to weight..or can I? If it matters the slab is 24x24 and the crack is pretty close to middle...about a 2 inch drop at the edge. The storage building will only be 20x12 or so.

thanks

[innerlooper]

I am going to build a storage building in the back yard at the site of the previous garage. There is a slab, but its cracked and just above grade level, and just barely. So question is, should I just go pier and beam on top of the slab, or is there a way to still use the slab? or at least get the lower sill boards off the ground (like using concrete pads). I have alot of heavy things that I would love to keep in there (engines for one) and cant roll around on peir and beam due to weight..or can I? If it matters the slab is 24x24 and the crack is pretty close to middle...about a 2 inch drop at the edge. The storage building will only be 20x12 or so.

thanks

This is a tough one to do "right" and not spend some money. I am not an engineer but I would advise to do things "right" and that means break up the old slab and use it as the base for a new slab. You would have to haul the concrete from the unused section. Using the broken up concrete under a new slab is considered OK as long as you have enough depth and reinforcement in the new concrete.

Structures have a way of morphing into more important uses, so a deck gets a trellis and then turns into a sunroom and then into a bedroom and then into a den. If there is any chance that the storage room will become living space, do it right. Pier and beam on the old slab is also possible, but unless you use ALL pressure treated material (including plywood) and fiber-cement siding, the termites will get in, as you are very close to ground contact. You can put heavy stuff on wood structure. Put joists on 12" centers and double up the floor plywood (the treated ply from Home Depot is usually soaking wet and needs to be stickered and allowed to dry first). You could put down 2x4 joists, as long as you feel any standing water/ flooding under the floor is OK.

[BryanS]

Why not just do a 4" reinforced cap (rebar/meshing), on top of the existing slab? Forget about pier/beam or any type of wooden flooring/support, treated or not...

EDIT: Do not break up the old slab and use it as a base. If you going to use the old slab as a base, just cap it, as-is (it's already settled). Otherwise, if you break up the old slab - get rid of it, and put in a new one. My opinion.