In San Francisco’s historical Showplace Square warehouse district, an architecture and engineering team with a clear vision and extensive technical expertise transformed a dilapidated, nearly 120-year-old former paint and lacquer manufacturing building into a stunning high-end speculative office space designed to withstand high-level seismic events.
Dubbed a “Cinderella transformation” by Retrofit magazine, which named the project a top winner in its 2023 Metamorphosis Awards, MacLac Building D has garnered nearly a dozen industry awards and accolades for its design excellence and soaring achievement as an adaptive reuse project.
Marcy Wong Donn Logan Architects, working in collaboration with Peter Logan Architecture and Design, brought GPLA on board as structural engineer of record to help reimagine and redesign the small, single-story red brick structure for its next phase of life. Built in the wake of the 1906 San Francisco earthquake, Building D is surrounded by four tall utilitarian buildings that were concurrently being redeveloped. The multi-building complex served as the headquarters and paint and lacquer production facility for the McGlennon Lacquer Company (commonly referred to as MacLac) for many years. It remained in operation until 2020, when Comstock Realty Partners purchased the property for redevelopment at the onset of the COVID-19 shutdown.
Over the next two years, the project team designed, engineered, and executed a remarkable rejuvenation of MacLac Building D, including an extensive seismic retrofit that will ensure its use for decades to come.
As originally constructed, the single-floor, 3,784-sq.-ft. building featured heavy timber flat-topped trusses spanning 48 feet, supporting a gabled roof on 20-ft.-tall unreinforced brick walls with pilasters and windows. Over time, the heavy timber trusses were modified to accommodate several levels of mezzanines.
The first step for the redevelopment team was to strip away the many prior additions and accumulated debris that cluttered the building’s interior to reveal its original brick, wood, and steel bones. GPLA worked in close collaboration with the architect to deliver on their vision for an open space that is lit by a new 60-ft.-long ridge skylight extending the length of the structure, with a central atrium and an occupied mezzanine on three sides. The abundant natural light streaming in from the skylight highlights the building’s historic brick walls and steel roof trusses.
A major component of this project was the substantial seismic upgrade that brought the building up to modern building codes. Moment-resisting frames around each of the existing pilasters, which included perforated steel plates, were incorporated into the design. A new 2,555-sq.-ft. mezzanine, made of cross-laminated timber (CLT) and featuring a perforated steel guard rail, is hung from the trusses, offering the impression that it is floating from the ceiling. GPLA accomplished this by removing the bottom chord of the old trusses and reinforcing the existing wood top chord with new steel angles. Hanging the mezzanine from the trusses allows the ground level of the building to be open and column-free.
“The earthquake retrofit became a beautiful architectural element that is now supporting this CLT mezzanine,” commented Gregory P. Luth, GPLA’s founder and lead engineer on MacLac Building D. “This project is quintessential GPLA: get together with the architect and find out what they are trying to accomplish, and then use our artistic as well as technical knowledge and imagination to come up with structural solutions that also create a beautiful structure that meets the architect’s vision.”
GPLA executed that vision utilizing HD BIM, designing and detailing all structural steel, rebar, and foundation components to LOD 400 in a single model from the beginning to end of the design and construction process. Shop drawings were produced directly from the Tekla design model.
The foundations design consists of continuous grade beams around the perimeter that are reinforced with prefabricated cages. This prefabricated component was selected in part due to the ease of placement and high degree of constructability by the contractor, a consideration for GPLA on every project it undertakes, Luth noted.
“Especially on a project like this where there were a lot of unexpected challenges that came up in the field, I call the superintendent every day to find out if there is a problem we can help them solve structurally,” he commented. “We’re not just part of the design team, but consider ourselves an indispensable part of the construction team as well.”
