My Question: Is there a standard method of protecting joist framework from topography where the terrains elevation is above the concrete stem wall; am I talking crazy, can it be reliably protected from rot? Should this be avoided at all cost? Does it pass code? CAD detail too, if available?

My Predicament: The house has a original footprint on a stem wall and 2 additions on concrete that step up internally 11 inches. This elevation difference is between pool and original footprint.

The plan is a complete removal of the additions and a rebuild on stem wall at the original homes elevation (despise concrete floors) hence removing internal step-up

Space is the issue; dropping the elevation of the patio to fall below the new construction stem wall and then back up to meet the pools elevation is almost 2', which would also include steps out of the house in an already extremely small patio footprint.

I appreciate; ideas, thoughts, Thanks in advance.