Every portion of a building or premises used or intended to be used for residential purposes shall comply with the provisions of this chapter irrespective of when the building was constructed, altered or repaired. Any alterations or changes of use which may be caused directly or indirectly by the enforcement of this code shall be done in accordance with applicable sections of the Building Code and Zoning Code. Rest homes, convalescent homes, nursing homes, hotels and motels shall be exempted from compliance with this chapter.