I'm putting together a design/bid for a raised patio to replace this... We already demo'd the existing structure (everything above grade, and all the slabs on the ground), and ran into a gotcha of sorts. The existing structure was built with CMU, the blocks are buried at least 4 courses below grade around the perimeter of the structure and in the entire area of the steps. Obviously, being 32" below grade, the blocks are holding onto quite a bit of water. All of the fill inside the structure was/is clay. Here's a quick layout of what may go in it's place... The red line is the foot print of what we took out. My question is, if I avoid placing my wall footings above the existing perimeter, can I avoid excavating/filling the existing block? If not, what should I do? Excavate just the buried CMU or excavate the entire area to the depth of the cmu/virgin soil? In either case, what should I use as fill? Clean 1.5" minus rock wrapped in textile (as we may do in the case of new construction)? Rip rap? The new raised patio will be 30" above grade and likely filled with 1.5" minus w/ fines (crusher run). What do you think the chances are the patio fill, wrapped in textile, will be stable enough to span the areas of buried CMU?