Ok Ok I now see what you were getting at with your first post the perimiter grade beams were used and or reinforced but the interiour beams were used as left by original consruction..There by the slope to the center I suspect that was what you where saying. but still do not understand the 18" foundation vents?? Only other thing is to check cabnets and counters to if it was built to compensate that slope if it was then it is what it is..