Developer packs boxes into backyards

Backyard Box's 800-square-foot option has two floors.

Efforts to increase density in Seattle’s residential neighborhoods finally reached fruition in December, opening up a new niche for recently launched Backyard Box.

Seattle-based Backyard box sells and installs detached accessory dwelling units (DADUs) to help owners of single-family homes on in-city lots take full advantage of the available space and the city’s new regulations.

Backyard Box offers three pre-designed models that range in size from 400 to 800 square feet. The structures are panelized so installation only takes about three months. They cost between $79,500 and $104,500. The company chose not to offer pre-fabricated buildings right now because the expense and complexity of installing a full unit in Seattle’s neighborhoods would be prohibitive.

It took years for Seattle to pass regulations allowing DADUs due to concerns from residents about on-street parking and that the city’s residential character could be lost. Based on his experience as an “urban eco-developer” who worked on some backyard homes in the city, Backyard Box owner Sloan Ritchie says he believes there is pent-up demand for the product. He is aiming to sell 10 units in his first year of operation but thinks the market in Seattle could eventually support 50 to 60 units a year.

All three designs are built to Passive House standards which will reduce heating costs by 10 times compared to a similar-sized house, according to the company. Options include a net-zero energy model, interior LED lighting, a solar hot water system, solar electric panels and a green roof. The company is sourcing its structural insulated panels exclusively from Tacoma, Wash.-based Premier Building Systems.