Lot Line Windows In Residential Buildings

By Johan Soltani

The DOB has issued Building Bulletin 2015-017 to clarify Code requirements for lot line windows.

Lot line windows, up to now, were basically permitted as long as they were not more than 10% of the façade of the floor where they are proposed and they are not to be considered for light and air. For merged zoning lots with the adjoining lots, these windows were allowed to be used for light and air to the habitable rooms.

This Bulletin clarifies it further specially if the zoning lot is merged with the adjoining buildings.

• 10% openings allowed for protected windows within 60 feet distance to adjoining structures. Lot line windows are not to be considered for light and air.

• 100% openings allowed for protected windows beyond 60 feet distance to adjoining structures. Lot line windows are not to be considered for light and air.

•  For buildings with merged zoning lot with the adjoining buildings, 10% openings allowed for protected windows within 60 feet distance to adjoining structures. These windows can considered for light and air.

•  For buildings with merged zoning lot with the adjoining buildings, 100% openings allowed for protected windows beyond 60 feet distance to adjoining structures. 10% Lot line windows can considered for light and air.

•  A provision is also added for building owners who can demonstrate hardship if the adjoining buildings are fireproof and sprinklered. For these buildings in a merged zoning lot, light and air is permitted for protected lot line windows. Within 30 feet 10% openings, between 30 feet and 60 feet 45% openings, and beyond 60 feet 100% openings. All the lot line windows can be considered for light and air.