BCCI braced the building’s existing walls to install the new roof penthouse structure. The existing wood-framed roof was replaced with a new steel, metal deck and concrete infill roof. This was done for seismic purposes and to prepare the roof for a vertical expansion of a penthouse and stone roof pavers that now rest upon it. In addition, the new Jacuzzi pool required significant structural support.
Interior Aesthetics
Inside, the scope of restoration work to the century-old structure included exposing the wood-joist structural system on the first-floor ceiling, which allowed the heavy wood timber beams and columns that connect to the structural system to be exposed. The modern glass curtain façade at the penthouse level, which opens to a roof deck, is a modern juxtaposition to the brick masonry walls of the original structure.
Another important element of the project, structurally and aesthetically, was the feature staircase that runs from the basement to the penthouse. It was designed to have a folded steel-plate effect. Fire analysis had to be performed to evaluate the stair, and BCCI and Holmes Culley worked with FME Architects to achieve the desired light-and-airy look.
To expand the existing space and achieve the required head height in the basement, the floor was excavated approximately 4 feet. Holmes Culley devised a construction sequence that would allow the existing wood columns to be shored while the existing pile caps were removed and the piles lowered to support a new concrete pile cap. A new steel stub post was then installed to underpin the existing wood column. The solution allowed the existing historic wood columns to remain exposed at the upper portion in lieu of replacing the columns. The basement now includes a fitness center and an oversized spa pool that sits below the foundation and the water table. A shear structural wall just beyond the pool maintains the mechanical system for both a koi pond and the spa pool.
717 Battery was unique for BCCI because of the combination of ground-up construction, seismic work, historic-renovation work, tenant-improvement work and the special amenities required. It was highly complex and required thousands of man-hours of collaboration between the architects, engineers and subcontractors. In addition, BCCI performed extensive design-build work on the project, namely on the spa pools, koi pond and various glass curtainwall systems. BCCI prides itself on high-quality product delivery; the company is always in pursuit of client satisfaction and strives to complete its projects at the highest level of perfection possible.
Although The Battery is a private, members-only club, many of the amenities are available for public use. For example, the main-floor lounge and second-floor conference center are available for banquet and conference rentals. Whereas select areas, such as the restaurant, bars, card room, library, fitness center and the plaza, are limited to members and overnight guests.
Retrofit Team
General contractor: BCCI Construction Co., San Francisco
Structural engineer: Holmes Culley, San Francisco
Core and shell architect: FME Architecture + Design, San Francisco
Interior designer: Ken Fulk, San Francisco
Photos: Blake Marvin