Have living room with concrete pad foundation that was added onto the house. The dining floor is about 3/8 inch lower than the concrete pad. We'd like to put engineered oak hardwood to the living room and pulled up the old carpet that was tacked onto it . So 5/8 in thick wood floor would lead to at least a 1 inch discrepancy between the living room and dining area (which has red oak floors that we are keeping as is). Is this too high ? The wall to wall carpet over padding didn't seem unnaturally high but don't know if two different wood floors of varying height would be weird. Don't know what the rules are on this. One floor store owner said it didn't matter as long as you mill a transition. The discrepancy extends along a width of about only 9 feet so it's not a huge length, but it's the main way into the living room.