For a mixed-use development, the Westlake 66 project in Hangzhou, China, was especially mixed up. Like many projects in this category, the development was initially devised to add a combination of offices, retail, hotels, and public space, weaving the different uses into a six-tower, multiblock amalgamation that would cover more than 2 million square feet. But between the start of the project in 2018 and its completion earlier this year, the exact mix of uses changed repeatedly.
The New York City-based architects behind the project, Kohn Pedersen Fox (KPF), turned that uncertainty into the project’s defining design feature. The entire project’s podium level has been wrapped with a cell wall facade treatment that can reconfigure based on whatever is happening inside the building. The modular system allows for a variety of exterior conditions on the building, from wide windows letting light into a boutique showroom to narrow tinted windows for a dim bar lounge to a louvered vent to let the building’s mechanical systems breathe. Should the uses inside the buildings change over time, the exterior could be adjusted to match.
Designing around uncertain programming is part of the reality of taking on big mixed-use projects, according to Jeff Kenoff, a design principal at KPF. “At any given moment, it’s a hotel, or it’s food and beverage, or it’s an atrium, or it’s something else. That was constantly changing throughout the design process and even during the leasing process,” says Kenoff. “One of the buildings was meant to be hospitality, but instead a university came in and said they wanted to do an urban building as part of their university system. So all of a sudden what was an office building became a school and a lab.”
“That’s a very different set of facade responses,” Kenoff adds.
Designing for uncertainty
To design for a project in such programmatic flux, KPF’s designers took lessons from something else that’s in a state of constant change: nature.
“We looked at biology and cellular structures, thinking about how that could be developed into a wall system that could change over the design process and then change over the lifespan of the building,” Kenoff says.
That led to the creation of KPF’s reconfigurable facade system, which is made up of 6-foot-tall cells that can take different forms to serve different purposes on the building. It’s not the first modular facade system KPF or other architects have designed for a building, but it stands out because of its adaptable form. The layout and makeup of the cells were largely determined by the program inside the project, but KPF also did extensive analysis of each cell’s location on the building in relation to its urban context and various environmental conditions. This analysis identified more than 2,800 unique conditions the cells would have to accommodate. Rather than making 2,800 individual cells, KPF’s computational design team determined that those conditions could be handled by a modular system of cells with just seven different apertures and a careful orientation around the building.
The seven apertures range from narrow to fully open. To make them interchangeable, the design had to be as modular as possible, so each cell has the same overall dimensions, and can be made from a menu of just 21 parts. Some of those parts are colorful terracotta liners that add depth and shading to the cells, while also referencing a local terracotta industry that dates back to the 14th century. The designers identified the five terracotta colors most seen throughout the city and echoed them on the building. They also used those colors for wayfinding, with changes in color indicating different parts of the project.
Another benefit of using the modular cell wall approach is that each cell’s small size, roughly 6 by 3 feet, meant that they could be manufactured as rectilinear objects but mounted out on the building with a gentle curve. Kenoff says this allowed a more creative facade that bends and bulges on the street level. “You really start to create public space on streets. You start to create plazas, arrivals, entries,” he says. “It was this push and pull that started to give a vertical program to the wall itself.”
The reconfigurable facade becomes a point of visual interest, as well as a draw for the tenants in the buildings, which include the university, retailers, a gym, and a luxury hotel, as well as a park space that sits atop the podium level and connects each of the six towers.
At least that’s what’s in the project now. Its mixed uses may change, and probably will. The facade can change with them, though Kenoff notes that such a reconfiguration would be more likely during a major tenant change. “The future-proof of this is we don’t know what’s going to happen in five years,” he says.
But for KPF, the cell wall is a lesson in how the firm can design around the uncertainty that comes with this kind of mixed-use project, or any project that may need to evolve over its lifetime.
“This is a never-go-back moment,” Kenoff says. “I don’t know how you would go back to an old way of approaching a problem like this.”