An approved single accessory building, including a garage, not to exceed 700 square feet, and a single accessory structure, not to exceed 500 square feet, may be constructed or moved onto:
a.
The lot where the existing primary residence is located.
b.
Any lot on the same subdivision and section which is owned by the same person who owns the lot where the primary dwelling is located.
The use described in subsection (a)(16) a or b of this section [§ 40-12(a)(16)a. or b.] is hereby approved without the necessity of obtaining a replat. If the property owner wishes to construct a garage or an accessory building in excess of 700 square feet, or an accessory structure in excess of 500 square feet, the property owner may apply for a variance.