Determining a building's official height can be a tricky process. We recently explained the different building height classifications, ranging from low-rise to supertalls, but today we'll explain how those measurements are determined in the first place. At Skyrisecities.com, we use the Council for Tall Buildings and Urban Habitat (CTBUH)'s Height Criteria to ensure the consistency of the information displayed in our Database, and to avoid any confusion amongst our readers. The CTBUH recognizes three different ways to measure a tower, as explained and illustrated below through the case of One World Trade Center in New York City

The Manhattan skyline, image by Kotsy

The first and most widely used height measurement technique involves measuring a building from its lowest, open-air, pedestrian and/or most significant access, to its architectural top. The architectural top of a building includes spires, but excludes all other functional-technical features such as antennas, signage, flagpoles, or lightning rods, as shown in the picture below. In other terms, this definition does not include equipment that may be removed or changed, or that was added later. This is the technique employed by Skyrisecities.com when determining the height of a structure.

One World Trade Center, image by Vlad Lazarenko via Wikimedia Commons

The second way to measure the height of an edifice is to consider its height to tip, meaning that unlike in the technique cited above, all functional-technical equipment is taken into account and considered as an integral part of the building. This measurement includes antennas, flagpoles, signage, etc. 

One World Trade Center, image by Flickr user Phil Dolby via Creative Commons, annotation added by Nicolas Arnaud-Goddet

Finally, the third technique used and recognized by the CTBUH to measure the height of a building is that of the highest occupied floor. Here, the highest finished and occupied level of the building is the reference for its height. The CTBUH specifies that an occupied floor is a floor that is used by residents or workers on a consistent basis, and does not take into account mechanical floors.

What do you think about these definitions and the way they influence the ranking of the tallest buildings around the world? Let us know by leaving a comment in the field below.