The Building and Zoning Inspector shall examine or cause to be examined every building or structure or portion thereof reported as or believed to be an unsafe building as defined in Section 1341.08. He shall give written notice to the owner of record, including any purchaser under a recorded land contract, and to the person occupying such building if he is not the owner thereof. The written notice shall specifically state the defects that cause the building to be unsafe and shall state that work shall commence within thirty days, either to complete specified repairs or improvements or to demolish and remove the building or structure, or portion thereof, leaving the premises in a clean, safe and sanitary condition, such condition being subject to the approval of the Inspector. However, in cases of emergency making immediate repairs necessary, the Inspector may order the changes or demolition to be made within a shorter period. The notice shall also require the building or portion thereof to be vacated forthwith by the occupants thereof.