Pavillion/Garage on pad on top of rock and clay

[forgeblast]

Look at the information on rubble foundations. A lot of alternative builders us them, also Frank Lloyd Wright was a big user of them.
It involves digging to structurally sound soil, then putting gravel and drain tile in. compacting as you go.
A lot of cordwood builders use them.

 

[pat32rf]

We hit bedrock about 6-20" down while building my BIL's 40x40' garage. Drilled the rock with 1" carbide bit, then inserted 3/4" re-bar with epoxy. Drilled holes up the center of 6x6PT posts for frame and set them over the rebar. Been up for 6yrs now and hasn't moved despite lows of -35 each winter. The building is unheated, with a gravel floor on high ground (no water to freeze), truss roof with no center supports, board & batten 14' walls (would have been 16' but our 6x6's were only 16' long

 

[Phast12]

What i've done in the past when working on big slab rocks that are down a couple of feet is to take a hammer drill and epoxy re-bar into the rock and then pour the rest of the footer making it wider than usual.