What is Permitted Obstruction?
Permitted Obstruction meaning A permitted obstruction is a structure or object that may be located in a required yard or open space or penetrate a height limit, setback area or sky exposure plane. A balcony, trellis, air conditioner, gutter or fence is a permitted obstruction in required yards or open space. Certain structures on a roof, such as elevator bulkheads, water towers or parapets are permitted obstructions that may penetrate height limits, setback areas or sky exposure planes.
reference: Glossary of Planning Terms – NYC Planning