Thanks!
It's framed with 2x4 & 6s then shelled mostly with 3/4" Oak Plywood, some 1/4" in areas to cover some of the 2x4s. I would have rather done 1/2" oak but neither Lowes or Home Depot carried the large sheets. Didn't add a lot of cost, just a lot of extra weight.
I'll have to add it up...