(a) In addition to all other powers and duties now conferred by law upon county commissions, county commissions are hereby authorized and empowered, by order duly entered of record, to adopt building and housing codes establishing and regulating minimum building and housing standards for the purpose of improving the health, safety and well-being of its citizens. Such codes may be adopted either for the entire county, or for any portion or portions of such county which may constitute an effective area or areas for such purposes, without the necessity of adopting such codes for any other portion of such county. Notwithstanding any other provision of this subsection to the contrary, no such code shall apply to or affect any territory within the boundaries of any municipal corporation which has adopted and in effect a housing and building code, unless and until such municipal corporation so provides by ordinance, or to structures on parcels of land used primarily for agricultural purposes.

(b) Notwithstanding the provisions of subsection (a), all existing county building codes are void one year after the promulgation of a state building code by the state Fire Commission as provided in chapter twenty-nine, article three, section five-b of this code.

Upon the voidance of the county's existing building code, if the county commission votes to adopt a building code, it must be the state building code promulgated pursuant to chapter twenty-nine, article three, section five-b of this code.

(c) In addition to all other powers and duties now conferred by law upon county commissions, county commissions are hereby authorized and empowered, by order duly entered of record, to adopt such state building code upon promulgation by the state Fire Commission. However, such state building code shall not apply to or affect any territory within the boundaries of any municipal corporation which has not adopted the state building code.