§ 1009.22 INTERIOR STRUCTURES.
   (1)   Compliance. No person shall occupy as owner-occupant or let to another for occupancy any dwelling, multiple dwelling, rooming house, rooming unit or portion thereof for the purpose of living, sleeping, cooking or eating therein which does not comply with the provisions of this division.
   (2)   Free from dampness. All cellars, basements and crawl spaces shall be maintained reasonably free from dampness to prevent conditions conducive to decay or deterioration of the structure.
   (3)   Structural members. The supporting structural members shall be maintained structurally sound and show no evidence of deterioration. The load bearing capability shall be as required by the Building Code.
   (4)   Interior stairs and railings.
      (a)   All interior stairs shall be maintained in sound condition and good repair by replacing treads and risers that evidence excessive wear or are broken, warped or loose. Every inside stair shall be so constructed and maintained as to be safe to use and capable of supporting a load as determined by the Building Code.
      (b)   Every stairwell and every flight of stairs shall have hand rails or railings as required by the Building Code.
      (c)   Every hand rail or railing must be firmly fastened and must be maintained in good condition. Properly balustraded railings capable of bearing normally imposed loads as determined by the Building Code shall be placed in the open portions of the stairs, balconies, landings and stairwells.
   (5)   Bathroom floors. Every toilet room floor surface and bathroom floor surface shall be constructed and maintained to be impervious to water and to permit the floor to be easily kept in a clean and sanitary condition.
   (6)   Sanitation. The interior shall be maintained in a clean and sanitary condition and free from accumulation of rubbish or garbage.
   (7)   Insect and rodent harborage.
      (a)   Every owner of a structure containing two or more dwelling units shall be responsible for the extermination of insects, rodents, vermin or other pests wherever infestation exists in two or more dwelling units or in the shared or public parts of the structure.
      (b)   The occupant of a dwelling unit in a dwelling or multiple dwelling shall be responsible for extermination within that unit when it is the only one infested.
      (c)   Whenever infestation of rodents is caused or permitted by failure of the owner to maintain the dwelling or multiple dwelling in a rodent proof condition, extermination of the rodents shall be the responsibility of the owner.
   (8)   Interior walls, floors, ceiling and woodwork. All interior walls, floors, ceilings and associated woodwork or trim must be maintained in a sound condition and workmanlike repair.