The subhead on Citylab's coverage of a new 47 foot wide pencil tower on 44th street in New York City asks "Can super-slender in-fill projects help NYC's housing squeeze?" The answer is, in a word, no, 47 times no. Kriston Capps writes:
The city is filled with narrow lots that are prime for infill development but don't quite command the luxury residential prices of Midtown near Central Park. It may nevertheless prove profitable—and possible—to build even narrower and taller on these lots to achiever greater density. That's at least a possibility.
Is it? When building this kind of tower the land cost per square foot of built area is probably extremely small. On the other hand, the construction costs are totally outrageous. Building codes demand two stairways, at least two elevators, fire protection equipment and other safety features for every single floor, no matter how small. This makes the tiny floors very inefficient. The exterior skin is the most expensive part of a building; when the floor plate is so small the ratio of surface to floor area is insanely high. On this building, there are big gaps for full floor gardens. According to the Daily News,
The concept represents a challenge for the engineers and architects, who plan to construct the building with limited structural support around the perimeters of the gardens, to avoid blocking the views. Instead, the structure will be held up almost entirely by the core.
Holding up the building while resisting wind and earthquake loads entirely by the core requires a huge amount of steel and concrete. Building on such a small site is difficult and expensive. As they say in the News, "Prices have not been released, but they will be high." Very high.
For every David Owen or Edward Glaeser who claims that towers are green and that New York should get rid of zoning restrictions, I want to point out these buildings' shocking inefficiency, the surface to floor area ratio, the tons of concrete per person occupying it. Given that 5% of the world's carbon dioxide comes from the manufacture of cement, these buildings are environmental killers. If there was any fairness or logic in how much embodied energy and carbon a single person was allowed to have, they would be illegal.
These towers are not part of the solution to New York's housing crisis, they are part of the problem. More on this in Related Links below.