I am creating an outbuilding, separate from my main structure. The main house has a standard raised foundation but the outbuilding is slab on grade. I figured out how to set the 'floor' height relative to the terrain but when I attempt to create interior walls with doors, the openings have framing at the sill of the doorways. I have moved the height of the doorways down so the sill is flush wioth the slab, but I feel that isn't truly the correct way. How do I best create interior partition walls beginning at the slab in a SOG room type like a garage?