Two for One

<strong xmlns="http://www.w3.org/1999/xhtml">A Lot of Use</strong>: What looks like a single-family home on the outside is actually two residences, each with its own private entry and patio space.

A Lot of Use: What looks like a single-family home on the outside is actually two residences, each with its own private entry and patio space.

Credit: Fred Kihara

Single people looking to live in the suburbs often find that their only option is more house than they can afford. Small rental cottages tucked in between larger homes might be one answer to that dilemma. The problem is that local zoning ordinances often make such structures illegal. So, when architect Rick Mohler wanted to add a rental unit to his 60-foot-by-100-foot corner lot in Seattle, he had to work the system. At the time, local zoning prohibited secondary detached buildings on residential lots. It did allow, however, accessory units that were attached. Mohler’s clever plan design introduces two separate “flip-flopped” dwellings (measuring 1,950 square feet and 1,000 square feet, respectively) that are connected by a 24-inch (per code) party wall. The homes have separate entrances, gardens, parking spaces, and corner windows but, from the outside, the structure looks like one house.

  • A Separate Peace: Architect Rick Mohler's suburban home shares a 2-foot party wall with an accessory unit, but you'd never know it. Each dwelling is an insulated box with 2x6 framing.

    Credit: Tim Matsui

    A Separate Peace: Architect Rick Mohler's suburban home shares a 2-foot party wall with an accessory unit, but you'd never know it. Each dwelling is an insulated box with 2x6 framing.

“I was interested in the idea of how to increase density in a single-family zone but still maintain the quality and character of single-family living,” explains Mohler, a partner in Adams Mohler Ghillino Architects and assistant professor of architecture at University of Washington. “In Seattle, 62 percent of the land area is zoned single-family, plus there are urban growth boundaries, so there is very little opportunity for multifamily in the suburbs.”

Mohler is now using the rental income from his tenant (a single woman) to offset his mortgage, but he also has the satisfaction of knowing his initial idea is gaining traction. After the Flip-Flop house was built, the city passed a “backyard cottage” ordinance allowing detached accessory units on residential lots—an alternative housing model that is now proliferating.

Affordability aside, this grassroots approach to infill could have other cumulative benefits in the ’burbs, he says. “If you can accommodate increases in density while maintaining the lifestyle people are used to, it opens up other possibilities. If you can increase your density by 50 percent to 70 percent, you are within shooting range of having the support you need for public transit.”