The foundations, floors, walls, doors, windows, ceiling, roofs, staircases, porches, chimneys, and other structural elements of the facility shall be maintained so that the facility excludes wind, rain, snow, and is rodent-proof, watertight and free from chronic dampness, weathertight, in good repair, and in every way fit for the use intended. Further, every interior structural element shall be maintained free from holes, cracks, loose plaster, or other defect which renders the area difficult to keep clean, or which constitutes an accident hazard or provides insect or rodent harborage.