A couple approached us to design an accessory dwelling unit – an ADU – for their home in Portola Valley that would take advantage of their property’s views and topography, as well as provide a living unit separate from the main residence which their family could enjoy during long visits.
Challenges to the site were its steep slope making site access and parking difficult to layout. The client’s inspiration imagery indicated a desire for an elevated structure, one that would maximize the dramatic views that the hillside property afforded. Our team quickly settled on the design of a structure projecting out over the sloping site, both to capture views and to create a covered, porte cochère-style area for parking.
The zoning requirements for the site dictated a maximum floor area of 800 SF for the new ADU, however the client wanted more space for living than the square footage requirements allowed. In order to meet both of these demands, AWA developed a centralized courtyard scheme which increased the daily usable space of the unit connecting the interior and exterior while being elevated above grade.
Prior to the start of the project, Portola Valley initiated a streamlined approvals process for ADUs. In order to qualify, the new ADU had to be compatible aesthetically with the main residence, and comply with certain height and earth movement requirements. While the project met the threshold of earth movement, it was not eligible because the proposed design exceeded the height limitation by four feet and consciously did not replicate the stucco modern farmhouse style of the main residence. The elevated design involved a complex structural solution and to meet seismic requirements.
Despite not being able to take advantage of the streamlined approvals process, the project was fast-tracked at the client’s request. Design began in the summer of 2019. Building permits were signed off on in late February of 2020. Construction was delayed by the onset of the Covid 19 lockdown in March, as the AWA and the consultant team adapted to working remotely, and site visits were kept to a minimum.
Material and finishes were chosen working virtually. While different stylistically, It was important to harmonize the new ADU with the main residence and the site, especially as one approached the property. It was a challenge to reduce the visual impact of the elevated unit which soars out of the hillside. Careful placement of the structure between and behind existing trees, and the meticulous selection of exterior materials, both schematically and during the construction phase, helped to blend the structure into the surrounding landscape.