For some modern houses it is difficult to determine Facing and Sitting. Always keep in mind that most structures have one Facing side and one Sitting side only. This rule may become more flexible when auditing apartments or business complexes, which will be discussed further down. Usually, and for a normal house, all floors will have identical Facings. However, some modern houses may be rented out in separate floors.
It is possible that each floor then has its own Facing, although you may of course not decide this being the case too easily.