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Pre-Approved Designs

What is a Seattle Pre Approved Design

Seattle has allowed the building of ADUs & DADUs for over 10 years. However, the rules & regulations around permitting were complicated and expensive, which did not lead to a significant increase in ADU/DADU construction.

In large part, Seattle’s housing crisis was the impetus for the Seattle city council to pass more lenient  DADU and ADU construction laws. An exciting feature of the 2019 upzoning regulations is the addition of pre-approved building designs that offer an expedited and more predictable design and permitting process.

Local architecture firms were invited to submit designs, up to 1000 square feet, for acceptance into a catalog of pre-approved designs.  ADUniversity’s website features the pre-approved designs.  Also on the site are photographs and descriptions of many other good designs but were not selected for the preapproval process.

DADU Choices

Choose from 10 pre-approved Backyard cottage designs.

Read descriptions and see photographs of pre-approved DADU plans at ADUniverse.  The pre-approved DADU design plans range in style and square footage.  In large part, the structures are adaptable to site conditions, environmentally sustainable, and offer several options to modify the space.

How to decide which design is best for your situation

Choosing a  model can be challenging with all the factors that need to be looked into. Aesthetics, logistics, opposing opinions, and budget need thoughtful consideration so informed decisions can be made going forward. Most likely, browsing the Seattle DADU designs will bring up more questions than answers.  This is where we come in with our experience and help lift the project off the ground.

In this initial phase, we will:

  • Help you choose the best model for your property
  • Contact the designer to procure the plans 
  • Prepare a Site Plan with the Pre-Approved structure on the drawings
  • Submit a building permit application

* A pre-approved plan expedites the process, and a permit can arrive as quickly as 2-6 weeks for most sites.

Ready to Move Forward?

Tell Us About Your Project?

    BBC manages every aspect of the construction project. Procurement, permitting, foundation, assembly, utilities, and a finishing touch.
    The ADU/DADU program currently offers 10 pre-approved designs from various Seattle designers.


    The Seattle DADU is 600 square feet of graceful aging-in-place and energy-efficient considerations

    Edge House - Bohlin Cywinski Jackson

    The minimal and simplified dwelling allows owners to balance distinct goals, skills, and budgets.

    Urban Cottage - Urban Cottage Prefab & WOOD Studio

    Urban Cottage offers a range of floor plans consisting of a studio (288 sq ft), one-bedroom (432 sq ft) and a two-bedroom (576 sq ft) dwelling unit.