26‑Story Apartment Rises in 5 Days: How China’s Steel‑Modular System Built a Tower Overnight

In an unprecedented feat, a 26‑storey residential tower rose in rural Hunan within five days, thanks to a fully prefabricated steel‑module system. The structure, known as the Jingdu Holon Building, was assembled from January 7 to January 11, 2024, covering 14,000 square metres of apartment space.

Broad Group’s Holon technology shipped a series of factory‑built modules, each measuring 12 m long, 3 m high and 2.4 m wide – roughly the size of a standard shipping container. Once on site, the modules were stacked, bolted together and connected to utilities, eliminating the need for on‑site welding.

Fully Equipped Units Arrive Ready for Installation

The company manufactures complete living units in a controlled factory environment, installing wiring, ductwork and other systems before transport. “Cranes lift the modules into place, workers tighten the bolts, and we hook up the services after the stack is complete,” said Jeremy Zimman, marketing director for Broad’s Holon modular building systems in the United States. The process, which requires no welding on the construction site, was streamed live on YouTube by the Modular Building Institute.

According to Zhang Yanwei, manager at Broad Group Holon Jianan Co., the finished tower incorporates stairwells, four elevators and eight 68‑square‑metre apartments per floor. The units are delivered furnished, and the Holon system includes air‑conditioning, ventilation, water tanks and other essential building services, though appliances such as refrigerators and washing machines are supplied by residents.

Stainless‑Steel Core Drives Speed and Strength

Broad Sustainable Building, founded after the 2008 earthquake that exposed vulnerabilities in concrete construction, opted for stainless steel as its primary structural material. The alloy’s resistance to corrosion and its ductility – the ability to deform without fracturing – are central to the company’s performance claims.

A patented floor system called B‑CORE forms the backbone of each module. The sandwich‑style panel consists of two stainless‑steel plates fused with stainless‑steel tubes, brazed at 2,000 °C with copper as a bonding agent. The Jingdu tower comprises 264 modules, split between residential and elevator sections, allowing flexible interior layouts while keeping the number of distinct part types low for mass production.

Two Cranes, Hundred Workers Raise the Tower

On the Xiangyin site, a crew of 100 construction workers operated in shifts, assisted by a mobile crane and a tower crane. The proximity of the site to Broad’s manufacturing plant simplified logistics, and the module dimensions – matching a 40‑foot container – enabled transport by flatbed truck or container ship.

Broad claims each module can be fabricated in just 21 minutes, while a 40‑by‑8 m B‑CORE slab is produced every two minutes – figures supplied by the company. The rapid off‑site production underpins the five‑day on‑site schedule.

Relocatable Design and Long‑Term Durability

Li Shun, general manager of Broad Group Holon, told China Daily that the stainless‑steel construction provides superior earthquake resistance compared with traditional concrete towers. He also highlighted the building’s insulation, which purportedly cuts air‑conditioning energy use by up to 90 percent, and noted that the façade and four‑pane windows mitigate noise and heat gain.

The company projects a lifespan of more than 1,000 years for the structure and asserts that the entire tower can be dismantled and re‑erected at a new location, a claim that aligns with its prefabricated design philosophy. Residents, recruited through a local talent‑attraction program, will enjoy rent‑free accommodation for the first two years, blending the construction showcase with a municipal housing initiative.

Modular‑building specialist Tony Frost, who spent a week in an earlier 11‑storey Holon tower in Changsha, described the interior as “sturdy, almost like a concrete structure,” praising the water‑filtration system that makes tap water pleasant to drink. He suggested that minor adjustments to interior finishes could further enhance the living experience.