Going rate for concrete

[JSUPreston]

If I'm looking at having to add 4", that would probably put me in the 10-11 yard range. Looks like building a frame and decking it may be the best solution. One advantage to it is that I can do 1/2 at a time and just move stuff around.

[LarryG]

His concern is with as much concrete as I could be looking at that it might blow out the walls, putting me in a much worse situation than I am in now!

That's nothing to worry about with your concrete block exterior walls. Slabs, even thick ones, are poured every day with far less substantial formwork to contain the wet concrete.

I agree that the area where only a thin topping slab is needed will be problematic. You'd want to use a high-strength concrete and ensure that it bonds well to the existing slab. It can be done, but it's dicey.

If there is a possibility, however remote or distant, of someday tearing the building down and building anew, that might be another reason to go with wood. A wooden superstructure could be torn out and the materials reused for something, whereas concrete will just have to be jack-hammered up and carted to the landfill.

[pelligrini]

There's other options than using standard concrete, especially in the 2" areas. There are a verity of lightweight mixes we use for subfloors, sometimes as the finished floor with burnishing & staining. Most of it going on top of wood framing.

We've been looking into USG's Levelrock too. It's a gypsum product like gyp-crete. Our office had a lunch & learn last week and took a good look at some of their new stuff. They've got a new high PSI 1/4" topping that comes in several colors.

[DUD]

I priced 2.75 cubic yards today for delivery next week. Here in Jonesboro it will run

$289.06 tax and all. It is for a slab in a storage building, 12' X 18'. Bill