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Back Yard Cottages in Seattle

by Sloan Ritchie of Backyard Box & Cascade Built. As of December 2009, the city’s new Backyard Cottage ordinance allows Seattle homeowners to build a second dwelling unit in their backyard. Why? Backyard Cottages provide affordable city living, housing flexibility, family-friendly housing options for extended families, and contribute to sustainable urban density.

By Sloan Ritchie of Backyard Box & Cascade Built

As of December 2009, the city’s new Backyard Cottage ordinance allows Seattle homeowners to build a second dwelling unit in their backyard. Why? Backyard Cottages provide affordable city living, housing flexibility, family-friendly housing options for extended families, and contribute to sustainable urban density.

How does this affect Seattle residents? Many residents meet the requirements for adding a second dwelling unit. These requirements include:

  • Single family home on at least a 4,000 square foot lot
  • The lot must be at least 25 feet wide and 70 feet deep
  • The owner must reside on the property at least 6 months a year, in either the primary house or cottage


Backyard cottages are very common in European countries where living small and having access to mass transportation are a part of everyday life. For Seattle, these units, which can be up to 23 feet tall or two stories, depending on lot width and roof type, and up to 800 total square feet, offer homeowners new options for guests, aging parents, adult children, home offices, a nanny, a retreat, or even a way to create new rental income.

Backyard cottages also have the inherent ability to change uses over time. For my family, it started as a home office and become a new way to create income.  For some, it’s a place where they can retire and a younger generation may live in the main house. And for others, it’s a space for the nanny to live and later a guest house for in-laws.

For our neighborhoods, I hope it means more people to engage with everyday, increased traffic for our local businesses and a notable shift towards the continued creation of a sustainable urban core.

Sloan Ritchie has lived in Seattle his entire life and is the founder of Backyard Box, a company that delivers modular and site built backyard cottages to Seattle residents and beyond.

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