Last week, in my post about the correlation between allowable FARs and building heights, I mentioned that I would be delving deeper into which zones are home to the tallest buildings. That’s what I will be exploring in this article.
To the data!
The starting point, as is so often the case, is PLUTO data. I will be using the same data that I referenced in last week’s article. The data covers the entire island of Manhattan.
If you’ve read my last article, you already know that I’ve done some calculations about building heights by allowable FAR. I expanded that model to include zones and then sorted by building heights in order to figure out the tallest zones.
Here’s what I found:
This table shows zones on the Y-axis and allowable FAR along the X-axis. As expected from my last post, when we sort the zones in order from tallest to shortest (as I did above), we get a trend that moves up and to the right.
This trend exists because allowable FAR has a positive correlation with building heights. The higher the FAR, the taller the building, on average.
The column on the far right is added for reference as a measure of magnitude. It is the total number of buildings within a given zone in our sample.
This is how you read the chart. The first zone, C5-2.5, has a maximum allowable FAR of 10 (from the top row), an average building height of 32.0 stories (the green cell), and contains 9 residential buildings (the column on the right).
Next, I’m going to throw this data into Carto and do a visual spot check. Which 9 residential buildings are in C5-2.5? Does this make sense?
If you know New York City real estate, the big red zone in the middle of the map will stick out like a sore thumb. That’s 432 Park, the 90-story residential skyscraper home to some of New York’s most expensive apartments. The dark orange building highlighted to its left is Museum Tower, a 53-story residential tower at 15 West 53rd Street. And to the south, just west of 3rd Avenue, is The Metropolis, a 48-story luxury rental building at 150 East 44th Street.
So it looks like we’re on to something. Simply modeling average building height by zone has enabled us to quickly isolate some valuable properties and create a hypothesis that zone C5-2.5 is great for tall buildings.
Warning: Digression Ahead
Now I want you to take a closer look at that map. Squint at the bottom left of the map between Park Avenue & Lexington Avenue and you’ll notice a very faint yellow rectangle. That’s 114 East 40th Street. And it’s only 9 stories tall. Weird.
In zone C5-2.5, we have 432 Park standing 90 stories tall, dominating the New York City skyline, and we have 114 East 40th Street rising just 9 stories.
Why? What other factors could create such an enormous disparity in building height?
Both buildings are C5-2.5 and both buildings are in the Midtown Special Purpose District (MiD). Zone clearly is not the only important factor in determining height.
432 Park’s lot area is about 10x the size of 114 East 40th Street’s lot area, but 432 Park has a building area of 745k SF whereas 114 East 40th has a building area of 26k SF — a 30x differential!
There is the added benefit of 432 Park being along a wide street, as explained in my post about setbacks. 114 East 40th Street was also built in the 1920s when the city was generally shorter.
But I think the key here, as reported by the New York Times in 2013, is air rights. 432 Park came with 115k SF of additional air rights before it was built. That enabled it to scale to great heights.
Unfortunately, there is no information about transferred or additional air rights in PLUTO data and I have not found a good source for this type of data, so we will have to live with the fact that we cannot account for air rights in our analyses automatically.
That said, we can still draw valuable conclusions. Zone C5-2.5 plus transferred air rights can lead to huge buildings. It’s something worth looking into for the other zones as well. For example, which sites are most favorable for applying transferred air rights?
Additionally, there is a lot more to building height than the zone in which a building sets and, therefore, there is a lot more to building height than allowable FAR (which is dictated by zone). Perhaps I’m inexperienced, but that’s news to me. The impact of air rights might be more meaningful than I previously thought.
Let’s get back on track.
That was a serious tangent. Valuable, but serious. Here’s the same breakdown for commercial land use:
It’s interesting that C6-6.5 has, on average, the tallest buildings, but it does not have the highest allowable FAR. I’m not exactly sure why that is, but I already bored all of you with one digression, so I won’t do it again.
Additionally, C5-3, C5-5, C6-6, C6-7, and C6-9 are all in the realm of 20-25 stories. If I were a real estate developer looking to build commercial skyscrapers, I would certainly focus on properties in these zones as a starting point.
This simple analysis has provided us with a foundation as to where the different zones stand in relation to commercial & residential building heights. I think it’s a quick and useful tool to help judge potential building height. On average, the zones towards the top of the list are going to be taller and inherently more valuable than the zones towards the bottom of the list. But that isn’t a definitive rule and it isn’t a suggestion that proper due diligence need not be performed.
As we saw with our comparison of 432 Park and 115 East 40th Street, zone is just one piece of the pie in attempting to figure out the key drivers behind building heights. I will continue to explore these drivers and use them to identify value where possible.