What makes a skyscraper a skyscraper?
Formulating a precise definition of what a skyscraper is goes beyond the intuitive image of a skyscraper we all carry with us
We all carry an intuitive image of what a skyscraper is. Yet, when we try to come up with a precise definition, the lines blur, and most of us start to lose confidence in our ability to formulate a clear definition once we introduce new variables and explore some edge cases.
Skyscrapers are tall buildings that reach for the sky, challenging engineers and construction companies to build what once seemed impossible. Skyscrapers are tall buildings that reach for the sky, challenging engineers and construction companies to build what once seemed impossible. Technological advancement has always been related to skyscrapers, from the development of steel-frame construction, which allowed buildings to rise taller without the massive load-bearing walls required by masonry structures, to the introduction of the modern elevator by Elisha Otis in 1857, which made it feasible for people to access higher floors without the impracticality of climbing stairs. These developments allowed buildings to explore new heights.
But there are variables other than height that are also important –and often not considered– such as proportion, use, urban context, or even some more abstract ones such as time and cultural significance.
Buildings that one-shaped skylines can be hard to spot in today's urban fabric–but once a skyscraper, always a skyscraper!
Let’s start with time. The Home Insurance Building built in 1885 in Chicago is considered by many as the first skyscraper, with only 10 floors! Before the invention of the modern elevator, most buildings in U.S. cities were only two to three stories high. Churches's bell towers were the only structures to challenge this otherwise flat skyline. A 10-story building in a city like New York or Chicago would be average at best today, but back then it was significantly higher than anything else around it, and therefore it was considered one of the first skyscrapers.
But are those still skyscrapers today? This depends on whether or not you consider that once a building is deemeda skyscraper it will always be a skyscraper. There is no right or wrong answer to this question, and even relevant institutions in the field often avoid answering it. If you ask me: once a skyscraper, always a skyscraper!
Height is a game of comparison. What's considered tall in one place can be just average in another
Urban context raises a similar dilemma to historical context. A 19-story-high building might be hard to spot in midtown Manhattan, yet it can stand out from its neighbors in Kansas City. So can the same building be considered a skyscraper in one city but not in another? There is no official answer to this question either. I’ve studied hundreds of architecturally significant buildings, and if you ask me, a building is never isolated; it’s always part of something larger; a community, a street, a neighborhood, a city... In my opinion, a building can’t be fully understood without its context, and therefore it makes sense that the 19-story high BMA Tower in Kansas City can be referred to as a skyscraper, while the 28-story high 461 Fifth Avenue Building in Manhattan, might just be considered “a building”.
Not every tall structure is a skyscraper. Before anything else, a skyscraper needs to be a building
Use is another important factor. Just because a structure is high–or even really high–doesn't make it a skyscraper. Radio masts and towers designed to support antennas are not skyscrapers. But what about communication towers that have elevators and allow people to go up to the top, where there might be even a few usable floors with restaurants, an observatory, and other amenities? Are those skyscrapers? The CTBUH (Council on Tall Buildings and Urban Habitat), the official institution when it comes to tall buildings, says that at least 50% of the structure needs to be occupiable for a structure to be considered a building, otherwise it’s just a tower. I agree with this definition.
Proportion is probably one of the trickiest variables of this mix. Buildings can sometimes deceive us by having a more or less slender silhouette. A thinner building can appear to be much taller than a less slender building of equal height. Let’s consider the Century Tower, completed in 1930 in Chicago with 28 floors and a height of 120 meters.
And let’s compare it to the Riverside Plaza Building, completed just a year earlier, also in Chicago, standing 92 meters tall with 29 floors, but with a floorplan shape that makes it way wider on one direction than on the other. An even more extreme example is the Merchandise Mart, a 104-meter, 25-story high building, also completed in 1930 in Chicago, but with a footprint so large it makes the building wider and deeper than it is tall.
Everyone accepts the Century Tower as a skyscraper, but what about the Riverside Plaza or the Merchandise Mart? The CTBUH acknowledges this dilemma but does not provide a clear answer. I, myself, seem to have trouble taking sides on this matter.
The proportions of a building also impact how we perceive its height. A short, slender building can be perceived as a skyscraper more than a taller but wider one
And if you think this is a problem that only applies to old buildings that were not so high by today’s standards, think again. The latest superstructures–and those that are yet to come– promise to challenge this concept even further. Think about projects like The Line in Saudi Arabia, a 500-meter-tall building that’s 170km long! Its proportion is clearly horizontal, yet it’s higher than the Empire State Building. Or the Mukaab, a building that’s 400 meters high (or higher than the Bank of America Tower in NYC) but has a footprint that also spans 400 meters in both directions, making it a perfect cube. Will we still call these skyscrapers?
Defining what makes a skyscraper is clearly a multifaceted endeavor that extends beyond mere height. We can’t know what the first people to look at a skyscraper felt, but they probably felt empowered and inspired. They probably saw those new supertall structures as embodiments of the ambition of their time, a testament to human ego and ingenuity, each telling a unique story of achievement and overcoming challenges. Each adding to the rich tapestry of our urban landscapes.
As we continue to push the boundaries of what's possible, both technically and aesthetically, our definitions may evolve. But perhaps that's fitting for a term that, at its core, represents the limitless reach of human imagination.
Think about one of the most iconic skyscrapers ever built–the Empire State Building. It doesn’t really matter how many taller buildings pop up in midtown Manhattan; it doesn’t even matter if 200 years from now you can’t even spot it in the skyline amongst a collection of other modern structures that are over a mile tall. The Empire State Building is, and will always be ingrained in American consciousness as a symbol of progress and resilience, especially during the Great Depression. Its stature goes beyond physical measurements, embodying the spirit of an era.
This probably means that we should not become so fixated on trying to fit things into strict definitions–definitely not skyscrapers–because ultimately, cultural perception, more than any hard-coded set of rules, will determine which structures become and remain skyscrapers, and which ones don’t. Because skyscrapers are as much a social and cultural construct as they are architectural ones.