Structurally unsound, loose, dangerous, crumbling,
missing, broken, rotted or unsafe exterior portions of buildings or
structures, including but not limited to porches, landings, balconies,
stairways, handrails, steps, sidewalks, walls, overhangs, roofs, fences,
retaining walls, supporting members, timbers, abutments, fire escapes
and signs, and loose, crumbling or falling bricks, stones, mortar
or plaster.