The heating contractor wants run a duct up from the cellar through the
living room floor and then turn 90 degrees to go through the wall to the
adjacent room that is on a slab. He says he'll box it in, but this will
leave an obstruction 8 inches out into the living room floor. Any reason
I can't remove a concrete block and come up through the sill plate and
run the duct up inside the wall? Any reason the contractor won't do it?

Bob