355 Eleventh is a LEED-NC Gold adaptive reuse of a historic (and previously derelict) turn-of-the-century industrial building. The building's original timber frame structure was retained and seismically upgraded. Both a new exterior envelope and new interior were provided to serve the building's current role as a multi-tenant workspace.
The 3-story, 14,000-square-foot mixed-use project was developed and constructed by the building's primary occupant; a general contractor specializing in green building. The general contractor's headquarters occupy the entire second floor of the building. The third floor is leased to an architecture firm. A restaurant and bar that has registered for LEED-CI Platinum certification will occupy the first floor and exterior courtyard.
Because the project site is on the National Register of Historic Places, the San Francisco Planning Department mandated that the project's new siding be an "in-kind" replacement of the original corrugated metal siding, which was unsalvageable, and that the overall window area be consistent between old and new. The design team successfully championed a strategy of introducing subtle perforations into the new zinc cladding to allow light and air into the occupied spaces beyond, maintaining the stoic character of the original building without the visual introduction of new fenestration.
While solar energy harvesting, a green roof, and natural ventilation make the largest quantitative impact on the building's overall sustainability, it is the new exterior skin that provided the most fertile territory for merging sustainability with architectural design.
The building's new metal skin is perforated with fields of small holes that allow light and air to pass through new operable windows hidden beyond. The perforated outer skin mitigates solar heat gain while enabling cross-ventilation of the interior. This rudimentary double-skin façade becomes a screen for sunlight and air without the visual impact of new fenestration on the historic facade. The new perforated skin results in a generously illuminated and well-ventilated interior, providing a pleasing view from within while simultaneously offering a degree of privacy for the occupants.
Rather than defaulting to pre-perforated panels, the patterning of the perforations was embraced as a design opportunity. Customized CNC (computer numerical control) milling allowed the creation of a seamless, building-scale gradient—from opaque to over 50% open—across the entire façade. This smooth gradient functions to dematerialize the industrial surface of the corrugated metal, gradually revealing the reflections of the glass beyond during the day and the warm glow of the interior at night.