All substandard lots must provide a minimum of three hundred seventy five (375) square feet of private open space in the rear yard. This open space must be configured as a fifteen by twenty five foot (15 x 25') open space (which includes the required setbacks). Of that required space a minimum dimension of ten by fifteen feet (10 x 15') shall be open to the sky. Covered unenclosed rear porches are allowed to be calculated as part of the private open space area. (Ord. 1263, 12-29-2011)