Urban Treehouse, a home as a sanctuary from the outside world

The program for this single-family residence of 2,000 square feet includes a large entertaining space (comprising open-plan kitchen, dining, and living areas), a master suite, and a pool with a guesthouse. Additionally, the client requested the entertaining space be a large volume and was particularly interested in the idea of a home as a sanctuary from the outside world. The primary design challenge was therefore to reconcile the client’s seemingly polar desires: to feel secluded, yet open; to be connected to the outside, yet separate from the city activity.

The design response is a uniform, rectangular mass with several voids subtracted to integrate and provide outdoor spaces within the small urban lot. The double-height, covered front porch provides cover from the elements at the entry and its large volume frames the street facade. A central courtyard is created by a void cut through the center of the mass, leaving a bridge connection between the more public entertaining room at the front massing, and the more private master suite on the second story of the interior massing. The effect is that the home, as perceived from the public right of way, is inviting and open. Several feet behind the front façade glazing is a full-height wall that performs several functions. First, it obscures much of the direct view into the entertaining room, adding privacy and the ability to seclude oneself. Second, it functions as a shear wall, adding rigidity to the frame required by the fully glazed opening. Lastly, it provides a utility cavity needed for plumbing fixtures and roof drains.

A small pool is located in the central courtyard and is connected to the central living space to the west and a pool house to the east both accessible through full-height sliding doors. With the doors open, the great room, pool, and pool house become one continuously connected space. By placing the swimming pool at the center of the plan, the design allows for the space to become a central gathering point when entertaining and also separates it from the commercial parking lot located adjacent to the rear property line, increasing the privacy of the pool area. The master suite, located above the pool house, is remote and private, but also entirely open in plan. Windows open the suite to views of the tree canopy above and the pool below. A clerestory of east-facing windows brings morning light into the suite.

Sustainable design strategies are integrated throughout this project. The entire structure is covered in a single roof plane incorporating cool roof design strategies through a reflective, white, single-ply roof membrane. The roof is also insulated with continuous, rigid polyisocyanurate, eliminating thermal bridging common in residential construction. The higher R-value wall section is achieved through a combination of spray foam and batt insulation, and a self-adhering building wrap was selected to provide a tighter envelope to reduce air infiltration. The voids cut in the building massing create shading that blocks much of the direct sunlight that would otherwise enter the home. For example, while the front façade is full-height western-facing glazing, due to the deep covered porch, and retained shade trees, minimal direct sunlight enters the home through these windows during the summer. In addition to these passive strategies, high-efficiency mechanical equipment was employed. Heating is provided through a radiant system on both floors via a high-efficiency boiler, which is substantially more efficient than a conventional forced air heating system. Energy efficient appliances are used throughout the house.

The residence limits impervious hardscaping and incorporates drought-tolerant landscaping. Water efficient appliance and plumbing fixtures are used throughout. The project was designed to meet LEED Gold certification, though certification was not pursued. Design strategies included incorporating day-lighting and natural ventilation with a harmonious relationship between building and site. The materials and finishes were sustainably-sourced and non-toxic throughout (reused, renewable and recycled content, low/zero VOC and low or no toxicity). The design team carefully selected and specified locally-sourced and sustainable materials and products whenever possible, and the home incorporates repurposed and salvaged products obtained from architectural salvage stores. Ongoing building maintenance was considered through low (or no) maintenance systems and materials in the design solution.