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Development Services

From Concept to Construction

Phone: 503-823-7300


1900 SW 4th Ave, Portland, OR 97201

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ADU Requirements

There are a variety of design and use standards in the zoning code which apply to the creation of an ADU. These include limiting the overall number of residents in both units, limitation with respect to home occupations, and the location of entrance doors and size of the ADU. Where an ADU is created in a new detached structure there may be additional standards regulating the exterior appearance and materials of the ADU depending on the height of the ADU. These additional standards include provisions for the roof pitch, trim, eaves and windows.

When converting an existing unfinished space to an ADU, some features, such as ceiling heights, windows, stairs and insulation, may not meet current building code requirements for finished space. These conditions could make it expensive, difficult or even impossible for you to change your attic, basement or garage into living space.

The ADU Program Guide outlines zoning requirements, construction standards, utility standards and other requirements in detail.