As prefabrication challenges traditional building techniques rapidly increasing construction speed to market, the question remains: when will prefabrication be feasible for skyscrapers?
According to Chinese construction company Broad Sustainable Building (BSB), prefabrication technology for sky-high projects is available now.
BSB gained global recognition when they constructed a 30-storey skyscraper in the Chinese city of Changsha in just 15 days using prefabricated units.
The company then announced it would build the tallest skyscraper in the world in an unheard of 90 days after the foundation for the building was laid.
The skyscraper will be known as Sky City and is expected to rise to 838 metres, surpassing the current tallest building in the world in terms of both height and construction time. At 830 metres,the Burj Khalifa in Dubai is currently the tallest building in the world, and that building took six years to construct.
The project broke ground this month but construction was halted due to safety concerns.
Sky City has drawn consistent controversy, with a professor of architecture at Tsinghua University calling the project "insane" and "the child of hot-headed government officials and technological geeks."
Despite these criticisms, BSB claims Sky City will be a pragmatic building.
“It is more than the world’s tallest building, but also an exploration on the healthiest way of living and the energy saving, land-saving and material saving building,” said Zhang Yue, founder and chairman of BSB.
Matthew Gaal, a senior associate at Woods Bagot in Melbourne and a member of the Council of Tall Building and Urban Habitat believes the technology is available for prefabricated skyscrapers but in terms of going “super tall,” it may be difficult.
“Anything’s possible,” he says. “I think you would have to seriously consider how and what you are prefabricating.”
Gaal also highlights the biggest industry advantage to the prefabrication of modular building technique: faster construction.
“Speed to market is pretty important,” says Gaal.
“If you’re talking super tall buildings, they have a long construction time and in that time anything can happen. The market can quickly change in that timeframe so the quicker you can get the asset (building) into the market, the better for the building owner and the building.”
Another misconception with prefabrication is that buildings that use the method are of an inferior quality, an argument Gaal says is untrue.
Today, as prefab materials are constructed in a managed factory environment and with factory inspections and repetitive processes, buildings that utilise those materials are considered of higher quality.
“The level of quality assurance goes up,” explains Gaal. “You’re not carting tiles up the building to go into level 50 anymore, they’re all tiled offsite and aligned properly.”
The factory environment also improves overall project safety for tradespeople who work at skyscraper heights, where conditions can be quite hazardous and congested.
Renowned Australian architect Nonda Katsalidis described tall buildings as dangerous to build.
“The higher we go the more difficult it is to get men and materials at those heights while respecting the ground. That is why prefabrication is so attractive,” said Katsalidis.
While there have been concerns of reduced employment with the implementation of prefab materials, tradespeople will still be required but will move from job sites to offsite factory environments according to Gaal.
In addition to faster construction times and factory located building assembly, prefab construction also brings environmental benefits such as a significant reduction in construction waste and reduced transportation impacts.
Forté in Melbourne currently boasts the title for the world’s tallest timber residential building and was constructed with prefabricated wooden panels.
Through the offsite manufacturing of bathroom modules and the cross-laminated timber structures, prefabrication allowed for a sustainable construction process.
Daryl Patterson of Lend Lease says prefabrication made for a more efficient and environmentally-friendly construction process.
“Designed and produced in a factory environment, Forté was 30 per cent faster to build, safer and with higher precision than traditional construction materials,” he told the Property Observer. "It also resulted in reduced construction traffic to and from site, caused less disruption to the community and produced less waste.”
Of course, prefabrication is not a foolproof panacea.
“It depends on how you go with prefabrication,” says Gaal, referring to minor restrictions that may occur with size and design as the method requires an extremely structured process. “As architects, we use all the opportunities to define what the project is, the unique quality of the building whether it has a freeway running past it, a flight path and all the different constraints that affect the building actually define the building.”
He notes that the benefits of prefab construction are evident, however.
“The quicker you build a building, the cheaper it is to build and it’s that speed to market which remains critical,” he says.
So while the industry awaits the fate of Sky High, prefabrication is revolutionising the industry and skyscrapers could rise quicker than anyone had ever imagined.