New Zoning Regulations Target the Use of Artificially Tall Mechanical Voids in Residential Towers

Land Use

Late last month, the city closed another creative zoning loophole exploited by developers of high-density residential towers in certain parts of New York City. In R9 and R10 zoning districts, commercial districts with R9 and R10 residential equivalents, and in some special districts, residential buildings can be developed as towers with generally no restriction on height. Essentially, the only bulk control that limits height is the amount of floor area assembled by the developer.

Of course, higher apartments mean better views and a jump in price. In order to achieve greater tower heights, some recent developments included artificially tall mechanical voids (i.e. voids that are taller than necessary to meet functional needs). These voids would exceed 80 feet in height, and would push up the building to make it taller. Developers would also cluster mechanical floors together in the lower or middle part of the building in order to maximize the height of these apartments. Since mechanical space does not count as zoning floor area, there is no incentive to minimize this space.

The new regulations target these artificially tall mechanical voids, and set forth that any mechanical floor exceeding a height of 25 feet will now count as zoning floor area. For tall mechanical space or stacked mechanical floors that exceed 25 feet, every 25 feet will count as another floor for zoning floor area calculations. For example, if a mechanical void is 100 feet in height, this will count as four floors and each will count towards zoning floor area. The restriction would not apply to penthouse mechanical space or below-grade mechanical space.

The new regulations also prevent improper clustering of mechanical floors by counting as zoning floor area, mechanical floors that are within 75 feet of one another and, in the aggregate, add up to more than 25 feet in height.

There was a mixture of support and opposition for this text amendment. However, most speakers at the hearings opposed the use of artificial mechanical voids to push up the height of a building. The debate was really about what is considered “excessive” or “artificial.” According to the City Planning Commission report, opposition speakers, including engineers, noted that, while mechanical space was traditionally located in the cellar or on the roof of buildings, industry practices are moving toward locating mechanical equipment throughout the building for better flood resiliency and energy efficiency. Some speakers believed that mechanical equipment requires more than 25 feet in height and that 30 to 35 feet would be a more reasonable threshold.

It appears that, in response to industry professionals, City Planning increased the threshold for mechanical voids to 30 feet. However, in approving the text amendment, the City Council further modified the threshold and brought it back down to 25 feet.

Posted by Daniel Braff