Project Overview
Minimizing material usage while maximizing visual impact can be a lofty goal in urban construction. When achieved, however, it can result in a stunning structure that doesn’t break the bank. 921 Howard in San Francisco, Calif., is a project that delivers much-needed affordable housing to the city’s Union Square neighborhood while establishing an ideal balance between aesthetics and constructability. In recent years, San Francisco has experienced a housing crisis, driven primarily by a severe lack of supply, exorbitantly high rents and home prices, and extreme demand. This project, which leverages a high-performance, thin-shell precast concrete envelope, provides much-needed housing to the city, all while delivering a structure that is as visually pleasing as it is resilient. Perry Architects Inc., in concert with Willis Construction Co. Inc., worked closely together to make 921 Howard possible.
A First in Affordable Housing
Standing at 18 stories, 921 Howard is San Francisco’s tallest fully affordable housing project. In designing the high-rise, Perry Architects and Willis Construction chose a thin-shell precast concrete exterior that would cover approximately 80% of the building’s exterior. A total of 357 unitized precast concrete panels, each spanning 32 ft in length and 10 ft 6 in. in height, were fabricated off-site using a cost-effective modular strategy. According to Dirk Pauels, associate for Perry Architects, the team used a thin-shell precast concrete system to overcome major logistical and design challenges, including COVID-19 pandemic–related disruptions, labor shortages, and budget pressures.
“The consistent panel geometry—with subtle articulation for visual richness—allowed for efficient formwork reuse and repeatable detailing, reducing costs while maintaining design integrity,” Pauels says. “The decision to fabricate and preglaze locally minimized shipping delays and ensured better quality control at a time when supply chain volatility posed significant risks to project timelines.”
About 80% of the panels were preglazed and caulked at Willis Construction’s facility, significantly accelerating the building’s enclosure while reducing on-site congestion. Installation of the interior bead of the two-joint sealant system was completed from within the building—an approach made possible by the consistent interior surface of the panel design and minimal obstruction from system components. Taken together, the use of precast concrete supported a safe, efficient, and weather-resistant construction process.
The project’s precast concrete panels incorporate two integral colors that were cast within a single mold and include geometries that transition from narrow window surrounds to deeper panel forms. These areas required careful detailing and reinforcement, pushing the limits of the thin-shell design. But thanks to this approach, the articulation of the façade creates a sense of movement and refinement, challenging the perception that affordable housing is only possible at the expense of aesthetics. Steve Perry, principal for Perry Architects, noted that the use of precast concrete on the project also reflects the design team’s forward-thinking approach.
“Precast concrete provided a durable, low-maintenance building envelope that will stand the test of time in a dense urban environment,” Perry says. “The use of cementitious materials with integral color reduces the need for repainting or façade treatments in the future, lowering operational and maintenance impacts over the building’s lifespan. Local fabrication reduced transportation-related emissions, and the system’s thermal performance contributed to the building’s overall energy efficiency goals.”
The 921 Howard project successfully delivered more than 200 affordable apartment homes in the heart of San Francisco, providing critical housing access to residents who have traditionally been excluded from new market-rate developments. Thanks to the use of precast concrete, the building sets a new precedent for design ambition in the affordable sector, proving that quality architecture, efficient construction, and social equity can coexist—even in a city where finding housing has been a challenge in recent years.
Mason Nichols is a Grand Rapids, Mich.-based writer and editor who has covered the precast concrete industry since 2013. |