Striking a balance between space and aesthetics in supertalls

For many new skyscrapers rising across Asia, eye-catching design or extraordinary height is a key part of the blueprint.

June 26, 2018

Beijing’s recently completed CITIC Tower has curved sides that evoke an ancient ceremonial wine vessel. Seoul’s Lotte World Tower, finished in 2017, is a slender cone. Jakarta’s Peruri 88, due to be completed in 2020, will feature four staggered towers.

Unique skyscrapers can be a big draw for companies looking for office space that conveys a sense of status. But for developers, creating prestigious form-driven structures often means sacrificing valuable space on the inside.

“A supertall building is an iconic part of many city skylines as developers and governments seek to create lasting symbols,” says Eric Lee, Head of Operations for JLL’s Greater China Property and Asset Management. “As more new and ever-more ambitious skyscrapers enter the construction phase in Asia, there’s a choice to be made between the conflicting demands of aesthetics and leasing space.

“The taller the tower, and the more irregular its shape, normally the lower the efficiency of its floor plan,” Lee says.

Building in the essentials

China in particular is home to growing numbers of the world’s so-called supertalls – a nickname for skyscrapers over 300 meters.

Developers building over this height must make sufficient room for electrical and mechanical shafts for running electrical cables and water pipes. Taller buildings also tend to have many thousands of people living or working across dozens of floors, making significant numbers of elevators with most advanced technologies essential to ferry the building’s population in a timely fashion.

All of these core requirements eat into available space, leaving skyscrapers with around 70 percent of useable space once compared to more than 80 percent in lower-rise buildings.

Meanwhile, the internal walls of supertalls also tend to be thicker to help reduce swaying caused by strong winds. Some even require extra columns for structural support. In short, supertalls have far less available space to lease.

“The efficiency ratio of some of the supertall buildings in China is below 50 percent, meaning only half of the space inside may be leased, whereas for a typical tall building, we are talking of a ratio more like 60 or 75 percent,” Lee says.

Plus, reduced usable space on these ambitious supertall or uniquely designed projects is often accompanied by higher construction costs to meet safety standards, make the buildings more resilient to high winds or earthquakes and ensure structures are in line with the increased focus on energy efficiency.

In Shenzhen, the Ping An Finance Center includes occupancy sensors, LED lighting, wireless daylight controls as well as lifts that generate power while in use and an AC system that responds to the users of the building.

Management costs are also higher. Mike Chan, Head of Property and Asset Management at JLL in Shenzhen tells Singapore’s Business Times that the cost of managing supertall buildings is around 35-50 yuan (US$5.5 to $7.8) per square meter per month in a first-tier city like Shenzhen, while the cost of managing a normal building in Shenzhen is around 26-30 yuan per square meter per month.

Higher rents for prestigious developments can go some way to offsetting other cost and lost space. Average monthly office rental rates in Beijing’s CBD, for example, are around US$50 to US$60, according to JLL while rents in supertall buildings are around US$80.

Using space effectively

Urban sprawl is an issue facing many rapidly growing Asian cities – especially with the number of people moving to urban areas only set to increase in the coming years. Dense, vertical city centers are an inevitable consequence as well as part of the solution.

Yet more needs to be done to utilise space in more effective ways, Lee believes. One straightforward way for developers to maximize their leasing efficiency is adhering to a square or rectangular floor plate. But that’s often not an option with unconventional design, Lee adds. Unoccupied space could also be used for energy efficiency measures from solar panels to channelling rain water or environmental data collection.

Nevertheless, the ongoing focus on form over function shows no sign of abating anytime soon in Asia Pacific.

“More mature, established companies tend to prize efficiency, but others, especially the big local enterprises in Asia, often feel that having an office in a unique building raises the overall profile of the company,” Lee says. “For that reason, they would be willing to pay more and make the most of smaller spaces to be in a supertall building.”

Yet maximizing value from the subsequent vanity height, the distance between a skyscraper’s highest occupiable floor space and its architectural top as termed by the Council on Tall Buildings and Urban Habitat, remains a key question.

New measures, such as Beijing’s recently proposed CBD height restrictions, will help to rein in some of the more ambitious designs but for Lee, iconic skyscrapers are synonymous with 21st century Asia.