Sliver buildings are taller buildings that have less than 45 width feet street frontage. The height allowances for sliver buildings are generally determined by the width of the street or 100 feet, whichever is less. Sliver buildings are not to be confused with towers. Towers are much taller than sliver buildings so they may appear thinner, but they lie on much larger zoning lots with wider street frontage. Developers typically build sliver buildings on tiny lots in high-rise zoning districts of Manhattan.

The Zoning Code doesn’t specifically restrict sliver buildings from any district, as buildings are subject to the height and bulk regulations of their district. However, districts permitting taller buildings (higher residential and commercial districts) are subject to the restriction in Section 23-692.

Residential districts subject to 23-692 are R7-2, R7D, R7X, R8, R9 and R10.

Commercial districts subject to 23-692 include C1-6, C1-7, C1-8, C1-9, C2-6, C2-7, C2-8, C4-4D, C4-5D, C4-5X, C4-6A, C4-7A, C5-1A, C5-2A, C6-2A, C6-3A, C6-3D, C6-3X, C6-4A and C6-4X.

However, heights are restricted in the following circumstances:

• Through or interior lot: the height cannot exceed the width of the street, or 100 feet, whichever is less.
• Corner lot bounded by narrow streets (75 feet or less in width): height cannot exceed the width of the narrowest street.
• Corner lot bounded by one wide street (75 feet or more in width): the height cannot exceed the width of widest street, or 100 feet. Whichever is less.

However, the above heights can be exceeded if any of the following applies.

• Wide streets: sliver buildings can match height of the building abutting it.
• Narrow street: Sliver buildings can match heights of the smaller of the two abutting buildings.

Street walls under the above circumstances have to be fully contiguous at every level with abutting street walls. This means that where the abutting building sets back, the sliver building must also set back. It cannot be closer to the street wall at any point.

The following rules must also apply to sliver buildings in these districts:

• Front height and setback rules from the underlying district shall apply (if they are more restrictive).
• Street walls of permitted obstructions or street walls beyond 100 feet of the street line are not permitted for sliver buildings.
• On narrow streets, a sliver building can’t be closer to the street line than the nearest of two abutting buildings.
• Sliver buildings on a through lot are exempt from rear yard equivalent requirements of Section 23-532.