Page 86 - Designing for Zero Carbon-Volume 2_Case Studies of All-Electric Multifamily Residential Buildings

CASE STUDY NO. 4 THE PALO ALTO APARTMENTS
(Opposite Page) Partial view of apartment building from Com- mon Open Space on the east side: two levels of apartments plus the penthouse level.
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Designing for Zero Carbon: Volume 2
Design Process and Low-Energy, Zero-Carbon Design Strategies
Sageleaf Forest was both owner and general contractor for the project, utilizing the traditional ex- pertise of architectural and engineering design professionals. Because of the approach taken for the design of the project, the company also added to the project team some firms specializing in building science (for waterproofing and airtightness), energy modeling and the high-performance building system known as Structural Insulating Panel System (SIPS). A construction manage- ment firm was also engaged to handle the day-to-day details of the construction process and to inspect the work on a regular basis and report on the progress.
The company carefully selected each firm on the project team for their specific role and was very hands-on throughout the course of design and construction. They carried out the California Title-24 energy code compliance, for example, as well as the detailed shop drawings of the SIPS system for the manufacturer. Such attention to detail helped ensure good coordination of the various atypical systems used on the project.
Building Program / Site Constraints
The architect’s initial task was to fit as many units as possible on the site within the city’s plan- ning and zoning constraints, incorporating all the amenities and features for each apartment. The basic program called for primarily two-bedroom apartments and one special four-bedroom penthouse unit on the top floor. The city parking requirement was significant: two parking spaces per unit and guest parking spaces. Since the area required for parking would be a major portion of the site, and since the height limit was dictated in part by a daylight plane1, it was decided to place the parking in an underground level. Although an expensive solution, this would allow the maximum number of units to be built on the site.
The final program developed was ten two-bedroom apartments, the single four-bedroom pent- house apartment and two additional three-bedroom apartments at the rear of the site (denoted ”townhomes” by the developer), for a total of thirteen apartments. The required parking for this program was thirty-one (31) spaces: twenty-six (26) for the apartments, four guest parking spac- es and one for the project’s small on-site office. Ample outdoor common and private deck spaces were fit into the efficient plan.
In its final configuration, the project consists of two buildings above one level of underground parking. The larger building, closest to the street, contains two levels of the two-bedroom apart- ments and a third level exclusively for the penthouse apartment. The second building, located at the rear of the site, consists of a pair of two-story apartments, which were able to accommo- date an additional bedroom in the available space. Because the full number of required parking spaces could not be fit into the below-grade level, the parking for the rear building units was designed as conventional garages on the first level. Ramp access to the below-grade parking level and first-level driving access to the rear garages occupied the remainder of the relatively- small downtown site.
The floor area of all apartments totals 22,500 gross square feet. The basement parking level has an area of 12,347 square feet, including an elevator and bicycle storage room. (See floor plans on the following pages.)
1 A daylight plane is an angled building height limitation that regulates the massing and design of buildings and defines the building envelope within which all new structures must be contained. Daylight planes are intended to provide for light and air, and to limit the impacts of bulk and mass on adjacent properties.