Whenever any structure is being used contrary to the provisions of said State Building Code, the Building Official may order such use discontinued and the structure or portion thereof vacated by notice served on any person causing such use to be continued. Such person shall discontinue the use within ten days after receipt of such notice or make the structure, or portion thereof, comply with the requirements of said State Building Code; provided, however, that in the event of an unsafe building, §§ 150.15 through 150.20 shall apply.