No lot, yard, parking area or other space shall be so reduced in area or dimension as to make said area or dimension less than the minimum required under this chapter. If already less than the minimum required under this chapter, said area or dimension shall not be further reduced.

No yard or open space required in connection with any building or use shall be considered as providing a required open space for any other building on the same or any other lot, except as otherwise provided herein.

No minimum off-street parking, loading or unloading areas shall be considered as providing off-street parking, loading or unloading for a use, building or structure on any other lot or parcel than the principal use to which it is ancillary, except as provided herein.