This subchapter applies only to a building or the structural components of the building that:
(1) is being used for office, retail, or warehouse use;
(2) is proposed to be converted from nonresidential occupancy to mixed-use residential or multifamily residential occupancy for at least 65 percent of the building and at least 65 percent of each floor of the building that is fit for occupancy; and
(3) was constructed at least five years before the proposed date to start the conversion.