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ADU & DADU Design

As the Puget Sound region faces unprecedented growth, AS Built Studio is deeply passionate about the role of “middle housing” in our communities. With an estimated need for over one million new homes in the coming decades, we believe that Detached Accessory Dwelling Units (DADUs) offer a vital, human-centered solution to our housing landscape.

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why we champion ADU & DADU

With an estimated need for over one million new homes in the coming decades, DADUs offer a path forward that respects both neighborhoods and the people who live in them.

01

Preserving Neighborhood Character

DADUs allow for increased density without disrupting the scale or charm of established single-family neighborhoods.
02

Building Generational Wealth

They provide a strategic opportunity for homeowners to create long-term equity and financial stability on their own property.
03

A Harmonious Way to Live

Private yards and quiet boundaries offer a dignified living experience — for young families starting out and older adults looking to downsize within the neighborhoods they love.

Our Process

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The Analytical Foundation

Before a single line is drawn, we conduct a rigorous regulatory and site analysis to determine your property’s true potential. We translate complex zoning envelopes, height calculations, and utility access into a clear, written roadmap — ensuring the design process begins with a complete understanding of what is permissible on your specific site.

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Purposeful Design

We believe a well-designed ADU is a high-functioning response to both the site’s context and your specific goals. Our process explores spatial logic, maximizing every square foot to create a home that feels surprisingly expansive. For clients focused on efficiency, we offer a streamlined path designed to optimize timelines and budgets without compromising architectural quality.
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Navigating the Path

Permitting is often the most complex phase of a project. We manage the entire process, serving as your advocate with jurisdictions like Seattle, Kirkland, and Bellevue. Our deep familiarity with local review processes allows us to reduce revision cycles and move your project through the building department with professional precision.

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The Collaborative Build

We remain your steward during the build phase. We provide detailed documentation to your general contractor, review submittals for design conformance, and conduct site observations to ensure the final home reflects the permitted vision. We also maintain a curated network of trusted local builders and can provide referrals tailored to your scope. 

ADU & dadu faqs

An ADU is typically integrated into the primary structure (like a basement conversion), while a DADU is a freestanding “backyard cottage.” Both are subject to unique zoning and setback rules that vary by city.
Feasibility depends on lot size and characteristics, existing coverage, and utility access. Our feasibility study provides a definitive answer before you invest in full design services.

Fees are structured by phase—feasibility, design, permitting, construction observation —to help you make informed decisions at every milestone. We provide a custom proposal following our initial consultation.

Typically, design requires two to four months, while the permitting phase in jurisdictions like Seattle can range from two to eight months depending on project complexities, and the city’s current workload.
Permit preparation and management are core to our service. We prepare all required documentation, submit on behalf of the owner, and manage communication with the building department through issuance.
A permitted, well-designed ADU typically increases assessed and market value. It also creates rental income potential in high-demand markets. We can discuss valuation considerations during the feasibility phase.

Proudly Serving

Seattle

Kirkland

Bellevue

Everett

Mercer Island

Greater Eastside

Every exceptional home begins with a conversation.

We invite you to share your vision and explore how our principled approach can bring it to life.
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