Like a blank canvas, an empty lot can be intimidating. Especially when it’s located on a block full of uniformly single-story houses. For a Cupertino couple that works from home, their cul-de-sac parcel at first presented two unhappy choices: construct a two-storey live-work space and risk alienating the neighbours, or build out and lose their back yard. “Making this space light and open, preserving some back yard, and fitting everything in was the main challenge,” says firm principal John Klopf. He presented the pair with a better alternative: lift the roof to create a massive north-facing curtain wall, while submerging the lower floor’s plate to add height to the subterranean space.

Angling the roof of the great room solves two problems simultaneously. The Joseph Eichler-inspired move, defined by black beams set against a contrasting white ceiling, allowed for the insertion of a tall window wall, adding generous views directly onto the back yard. Because this high-performance glazing faces north, it brings in copious daylight without significantly contributing to heat gain. Sloping the roof downward to the south, the architects were able to cover it in solar panels; the 13.4 kilowatt photovoltaics are able to generate enough electricity to meet all the house’s energy needs.

Within the great room cabinet tops, cabinet bottoms, windows and doors are all aligned to specific horizontals. In Klopf’s words, “The alignment intentionally doesn’t draw attention to itself, but appears ‘as it’s supposed to be’ so people in the space don’t even question it. The point is for everything to be at rest and orderly, which means people can clear their minds and just enjoy being in the space.”

Below the great room, the partially submerged lower level features a strip of clerestory glazing. It provides a view onto the backyard, where an exterior stair leads down to the space through an excavated well, creating an atrium effect. Also, the great room’s light well, encased in glass and shelving, channels light from the main floor even deeper into the lower level’s southern reaches. The result is a basement that feels much more like a naturally illuminated ground-level space.

Using a combination of high-performance windows, structural insulated panels and insulated concrete forms, as well as cladding the house with cementitious siding, Klopf was able to achieve a high level of efficiency – which allows it to stay temperate using only its PV-generated electricity – while also remaining virtually termite-proof. The result is a spacious but low-maintenance home that the owners can enjoy for years to come.