Cob kitchen without foundation.

Stone is too expensive in my town, the ground where I want to build it is solid rock, is been hustle digging the trench, I understand the importance in keeping cob walls of the ground and dry, but what if I did a sandwich of geotextile, geo Membrane and again geotextile around the cob "foundation" all the way above ground level? My wall would be 250cm high from ground level up and 50cm thick.

Stone is too expensive in my town, the ground where I want to build it is solid rock, is been hustle digging the trench, I understand the importance in keeping cob walls of the ground and dry, but what if I did a sandwich of geotextile, geo Membrane and again geotextile around the cob "foundation" all the way above ground level? My wall would be 250cm high from ground level up and 50cm thick.