Except as provided in this section, existing buildings when altered or repaired as herein specified shall be made to conform to the full requirements of this chapter for new buildings:
(a) Alterations and damages over 25 percent. If the cost of alterations or repairs, as described herein, or damages by fire or other cause, is over twenty-five (25) percent of the physical value of the building, the director shall determine to what degree the portions so altered or repaired shall be made to conform to the requirements for new buildings.
(b) Alterations under 25 percent. If the cost of alterations or repairs described herein is twenty-five (25) percent or less of the physical value of the building, the director shall permit the restoration of the building to its condition previous to damage or deterioration with the same kind of materials as those of which the building was constructed; provided, that such construction does not endanger the general safety and public welfare and complies with other provisions of this chapter in respect to existing roofs.
(c) Increase in size. If the building is increased in floor area or number of stories, the entire building shall be made to conform with the requirements of this chapter with respect to means of egress, fire safety, light and ventilation.
(d) Part change in use. If a portion of the building is changed in occupancy or to a new use group and that portion is separated from the remainder of the building with the required vertical and horizontal fire divisions complying with the fire grading in this chapter, then the construction involved in the change shall be made to conform to the requirements for the new use and occupancy and the existing portion shall be made to comply with the exitway requirements of this chapter.
(e) Physical value. In applying the provisions of this section, the physical value of the building shall be determined by the director and be based on current replacement costs. (1975 L.M.C., ch. 1, § 1; 1980 L.M.C., ch. 56, § 1.)