Lot areas shall not be less than 7,500 square feet with the minimum setbacks prescribed, except that if a lot of record prior to adoption of this chapter has less area, frontage, depth or width than herein required, such lot may be used for a detached single-family residence and for such accessory uses permitted in the R-1 District, provided that:
(1) The lot area is not more than 10% short of minimum requirements.
(2) The lot is not contiguous to other vacant lot(s) in the same ownership.
(3) The minimum setbacks are adhered to.