I am in the beginning stages of planning a 32x48 detached shop on my property. I was originally going to set 2' x 2' x 4'8" piers and frame a 2x12 PT floor system on top of those. I just received a quote to set and backfill approximately 15 of these piers and the price was $10,000. There is grade change from front to back, but I plan to build up off the piers with 8x8 PT so I have a level floor. This was about 3 times higher than I had anticipated so now I am looking at other options.
I want to have a wood floor with some accessible space beneath to run my DC. Code requires that if I use piers they must be frost protected.
Do I use sonotubes or another kind of footing tube? Find a more level location and re-price the piers vs. a slab? I don't mind putting in some manual labor to cut down on the costs, just want to look into alternatives without compromising the strength of the foundation.
Any thoughts on this would be appreciated. Thanks in advance!