What soffit and bulkhead framing covers in a Louisville basement
We measure what is actually up there first. The trunk duct, the main drain, the gas line, the steel beam, each at its real depth. Then every box gets framed to the thing inside it.
Running one uniform depth across the whole ceiling is faster to build and it is why some quotes bury the room under a foot of soffit. Framed tight to each run, most Louisville basements keep seven and a half to eight feet across the majority of the floor, with the low spots confined to where the duct genuinely sits.