A Zero-Energy Community: Part 3
Project Manager Brad Liljequist chronicles the building of the zHome, a ten-unit townhome in Issaquah, Washington—the first multifamily zero-energy community in the United States. Part 3: A Q&A With David Vandervort Architects.
For our blog today I am going to interview David Vandervort and Mark Weirenga with David Vandervort Architects, the Seattle-based architectural firm that designed zHome. They have a long history of sustainably designed single-family homes and remodel projects along with extensive low-rise multifamily experience. Their projects include the sustainable demonstration project NEXTHouse and an award winning LEED Gold custom residence. I have really enjoyed working with David and Mark over the last several years and deeply appreciate the “homey modern” aesthetic they brought to zHome—modern design that you’d actually want to live in.
How did David Vandervort Architects become connected with the zHome project?
zHome represented, for us, an opportunity to bring together our deep green residential construction experience with a very progressive multifamily dwelling project. We saw it as an opportunity to holistically fulfill many of the sustainable goals we have been advancing since the inception of the firm.
Even before being selected for the project we developed an initial concept that introduced the ideas of shared outdoor space, common gardens, green walls, and renewable energy integration that became the design framework for the eventual project. These ideas resonated with the project stakeholders and developer and we were ultimately selected to see the design through to reality.
How did you perceive the zHome site?
Issaquah Highlands is a transit-oriented development in a suburban area east of Seattle. The tight .4 acre site set aside by the City of Issaquah was located in the more urbanized core of this community. We felt that it was important to maintain the active urban streetscape while also providing for a distinct sense of privacy for the inhabitants. Along with this there was a need to maximize the south facing site for energy generation and a desire to maximize this exposure for the health and enjoyment of the occupants.
We considered carefully how we would create a community within the Highlands that fit with the character of the place, but, since zHome was a unique and potentially influential project, we wanted to give it a forward thinking identity that promoted both the technological aspects and the community oriented aspects of sustainable living.
As architects, what are you trying to achieve with the design of zHome?
With the need for solar access, the desire for an engaged but private streetscape, and the goal of a shared common space, our design solution for zHome began to focus around a common courtyard. This “Solar Courtyard”, as it came to be known, created opportunities for connection: connections with neighbors, connections with the community at large, and connections with our environment.
Along with a community focus we also felt it important to maintain a sense of privacy for the individual dwelling units. To facilitate this we located the main living areas on the second floor and utilized decks and porches as modulating spaces between the units and the common space. These can be provided with screening devices for further sun and privacy control. In order to still maintain a direct connection to the courtyard each unit also has a flexible ground floor space that opens up to the courtyard and can be used as a home office or additional gathering space.
In a departure from the typical townhouse model, motor vehicles were relegated to the periphery of the project. Access strung along the north edge of the site allows access to congregated garages and promotes interaction with the courtyard even if arriving by car. The street has also been equipped for the parking and charging of electric vehicles. But the interior of the site is free of vehicular access and available for the enjoyment of the occupants.
In what ways is zHome a new model for living?
Many current townhouse projects are conceived of as a miniaturized version of the single family dwelling, with discreet living spaces, garages and landscape. At zHome, we are creating a model that prioritizes shared resources. The courtyard is a place that can be used by all occupants for community events and parties. The landscape is established for mutual benefit and includes edibles, herbs and native species. Rainwater is harvested on the site and stored and shared among the dwellings. Overflow storm water is celebrated and infiltrated at the entrance to the community. Ground source wells for heat and hot water are equally shared by all dwellings. Even recycling, waste disposal, and a gardening center have been considered and given a single shared structure that accommodates all of these functions.
Inside the dwellings, we took the approach that the quality of the space is just as important as meeting the technical energy benchmarks. The dwellings have access to light and volume by incorporating open lofts into double height spaces. Outdoor decks and patios at all levels extend the available living space and help to create a buffer between private space (inside) and community public space (courtyard). Finally, reflecting the variety of modern living these dwellings are provided with open and flexible spaces. In many units, ground level spaces are provided that can be configured as a single large open room, or divided for use as multiple spaces. These spaces can be bedrooms, living spaces or home offices.
How did the technical aspects of the design integrate with the architectural design process?
The technical benchmarks of the project were a significant influence on the architecture and we were fortunate to be teamed up with a comprehensive consultant team. From the initial charette, throughout the design of the project, this team proposed and evaluated strategies that were then integrated into the project. Some of these strategies presented design challenges – creating enough roof area to generate the required photovoltaic energy, selecting appropriate fenestration and maximizing the limited glazing area, integration of natural ventilation schemes and allowing for the additional wall thickness required for high insulation values. It was important to us that the livability and architecture of the project not be diminished by the technical demands of the project but that they would be carefully integrated.
How can zHome help inform future residential design and construction?
On a technical level, there are many lessons that zHome can teach us. Many of these are covered in other postings of this blog. However, an overriding lesson we take from this project is that many of the strategies employed are not cutting edge, radical, or expensive. The planning of a project this compact and efficient is just as important as integrating high-tech equipment such as heat pumps and photovoltaic panels. Good design and quality construction should be the starting points for everything we build.
We also believe that a well-designed community space is a huge benefit to small multifamily developments. These spaces provide opportunities to connect with each other and the natural world. It is our hope that zHome will be a place where community resources and individual needs are carefully balanced.
Architect: David Vandervort Architects
Landscape Architect: Dar Webb Landscape Architects
Interior Design: LH Design
Energy engineer: WSP/Flack+Kurtz
Mechanical engineer: Stantec
Civil engineer: Core Design
Structural engineer: HSV Engineers
Low impact stormwater/rainwater design: 2020 Engineering