The goals of the project as set by the owners are unifying the existing house and detached garage, not replicating the existing house due to cost, having a storage loft, a patio, and additional off-street parking for the Detached Accessory Dwelling Unit (DADU). To respond to these goals, a simple concept is deployed. The existing house is a hip roof (double hip to be exact) and the existing detached garage is a gable. To unify all those structure into one design, a single slope roof (shed) is proposed but diagonally upwards toward the existing house’s peak of the roof (the slope is similar to the existing house). This way, formally, both the DADU and the garage will be subordinate to the existing house but complement it by creating the roof line as if continuing down from the existing house. The other ulterior motives are to collect the rainwater into a single lowest point for rainwater harvesting using a cistern and to allow storage loft to be tuck in below the highest point of the roof on the southwest side (towards the existing house, away from the neighbor). The collected rainwater will be used for watering the garden (one of the owners is a gardener).
The existing house was built in 1912 with shingle siding on upper level and lap siding below but the existing detached garage (built in 1993) has a vertical siding. While the existing house windows are vertically oriented, the existing detached garage has horizontally oriented fenestration (the garage door). Both have asphalt shingle roofs and are painted the same color for the body and trim. To be contextual without copying them, the proposed siding for the DADU is horizontal lap siding and painted the same color (as the existing house and detached garage) while the windows are both vertically (as the existing house) and horizontally (as the existing detached garage) oriented white double hung, picture, and awning windows for fire escape (double hung window) and natural cross ventilation (awning window) as well as maximizing the daylight into the DADU (picture window). The siding corner and window trims for the DADU are articulated trims (instead of flat against the exterior wall) but painted white, the same as the existing house. All of these are simple and affordable reinterpretation of the current available craftsmanship. In addition, simple overlapping woodwork and exposed structure for the patio sunshades (facing south at the high side) are painted white to, again, emulate current available craftsmanship.