ADU 101

Accessory Dwelling Units (ADUs) have become more popular and acceptable in the past few years. The City of Seattle began allowing for ADUs in all residential zones (it had previously been only some south Seattle neighborhoods) in 2009. San Juan County allows for a limited number of permits for ADUs each year. The number of ADUs proposed each year has not necessitated use of the lottery system for permits, which was conceived before the recession.
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Lopez_ADU_web

Lopez Island House, garage with attached Accessory Dwelling Unit, Lopez Island, WA
(Original design: D+A Studio) See more of my ADUs.

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An ADU can be attached, as in a basement apartment, or detached, as in a backyard cottage, carriage house, or alley flat. The implementation of ADUs can fulfill many goals of sustainable development, including [not so scary] density, affordable housing, and smaller house sizes. As our urban fabric is “re-knit”, neighborhoods can become more dense, creating more demand for services, therefore creating more opportunities for walkable neighborhoods and less dependence on a car.
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The concept of ADUs resonates with many things happening in housing currently: attractive central cities with high barriers to entry for home ownership, long commutes, lack of diversity in housing typologies, social isolation. Slowly adding a few ADUs in established neighborhoods can add density without inherently changing the character of that neighborhood.
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Truly sustainable development also includes social goals, many of which are also met by integrating ADUs: a way for homeowners to have a separate income stream, a mix of income and ages; the ability to stay in one neighborhood through varying phases of life, therefore creating lasting community: kids can live in a backyard cottage as they start on their career path, elderly parents or relatives can live in smaller spaces that require less upkeep and be close to their children and grandchildren. Extended families can live close together. Friends can create a casual co-op. An ADU can be a “tiny house.”
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The term “mixed income” may be worrisome to some, but from a social standpoint, renting out an ADU can more successful than an absentee landlord renting a house, in that owners are close to the rental unit, tenants are close to their landlord, so each keeps an eye on each other. The Kentlands Development in Maryland (designed by New Urbanism pioneers DPZ)  is a neighborhood that has successfully integrated market rate, large suburban housing with backyard rental units. An oft-cited example is of a woman who lived in her ADU and rented out her large house in order to save money and pay off her mortgage.

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At D+A Studio, we developed a full catalog of stock plans perfect for ADUs, backyard cottages, guest houses, vacation retreats or just simple living. Since the website for this catalog is no longer online, please contact me for more information.

Next week: A closer look at ADU rules for the City of Seattle.

An update to my original post ADU 101