A. 
No lot shall be reduced in area or in its dimensions so that:
(1) 
The new distances between buildings and street lines, lot lines or other buildings on the same lot shall be less than the distances required under the provisions of this chapter;
(2) 
The lot area per family shall be less than the area required;
(3) 
The percentage of lot area occupied at the level of any story shall be greater than the percentage permitted to be occupied; or
(4) 
The dimensions or area of any court, yard or other open space shall be less than the dimensions or area required.
B. 
Subsection A(1) through (4) shall not apply to previously existing dimensions.