Adu Design

Refine Design Architecture

Your ADU design partner.

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At Refine Design Architecture, we design ADUs and mother-in-law suites that suit your property and the way you plan to use them. Whether you want passive income, a smaller place to downsize into, or space for extended family, the right solution depends on your lot and your goals. We design each unit as a self-contained home with a kitchenette, bathroom, and living space, and we make sure it complies with local zoning. Our aim is a unit that blends into your existing home and neighborhood.

Meet our Residential Architect Team
The snowy exterior of a cabin in the woods. The cabin features an A-frame entrance to shed snow to the sides of the entry.
The image showcases a stylish interior remodel by a residential architect, connecting dining and living areas with a wood wall and open shelf feature.
An aerial view of a custom residence. The residence is three wings connected with glass hallways that allow passive heating and cooling. A stunning custom home designed by the residential architect, featuring modern lines, expansive windows, and a welcoming outdoor space.
Modern kitchen with wooden cabinets, gray island, four wooden stools, and stainless steel appliances.
Bright modern kitchen with white cabinets, a large island with cooktop, and sliding glass doors leading to an outdoor patio where two people are talking.
Modern mountain home with stone and wood siding, snow-covered ground and trees, and a black SUV parked outside.
Modern staircase with vertical wooden slats, beige carpet, potted plant, and narrow window with outdoor view.
This elegant interior showcases a custom bookshelf designed by a residential architect, featuring sleek lines and integrated lighting for a modern touch.

What can we do for you?

Learn More
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01. Pre-Design

We start by listening to your goals, your lot, and your budget. We review local zoning and permit requirements early, so you know what an ADU can look like on your property.

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02. Design

We develop several design options with floor plans and 3D renderings. Each shapes a self-contained unit with a kitchenette, bathroom, and living space that fits your lot and your household.

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03.  Permits

We prepare your permit drawings and handle the submittal. If the city or county has comments, we respond and resubmit. We can lead the process or support you through it.

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04. Construction

You receive construction drawings detailed enough for a general contractor to build from. We can help you vet builders and stay involved during construction to keep the project on track.

Don't just take our word for it.

Here's what our clients have to say.
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"RD's team provided us with a very special creative process designing our home...If you are seriously looking to elevate your next project, work with Refine Design!"
Shy F.
Mountain Lodge
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"Stone and Julia were very professional and extremely helpful in designing our project. Their patience and attention to detail were integral in configuring a change of use building."
Dustin D.
Ballard DADU
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"They not only helped bring our vision to life, but offered a point of view we had not thought of.  I highly recommend this duo - they are incredibly easy to work with."
Kendall F.
Gig Harbor Remodel
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"No words can describe how exceptional Julia and Stone are at their work...Not only did they research extensively into the building codes but they poured so much thought into the design."
Yu Chi S.
Seattle Bathroom Remodel
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"It was great working with Refine Design Architecture for our cabin expansion. They listened to our requirements, offered feedback and produced designs that fulfilled our vision"
Antonio G.
Leavenworth Cabin Addition
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"Their work was on schedule, on budget, and their ideas were very helpful. If you're searching for an architectural team that can fit the bill, look no further."
James M.
Accessibility Retrofit

Have questions?
We have answers.

An ADU is never a one-size-fits-all project. Your lot, your zoning, and your reasons for building all shape the design. Here are answers to the questions homeowners ask us most.

What is the ADU design and build process?

An ADU project follows the same five phases we use on every home: Pre-design, Schematic Design, Design Development, Construction Documents, and Construction Administration. In pre-design we learn how you want to use the unit and review zoning, setbacks, and other site limits. We then develop design options, prepare permit drawings, and handle the submittal. After permitting, we provide construction drawings for your builder. For existing homes, we measure the current construction and build a 3D model of it, so the new unit fits the house and the lot.

Do I need an architect to design my ADU?

Requirements depend on your jurisdiction and the type of project. The firm states that an architect is not legally required for custom homes unless the project includes four or more units. Legal minimums are not the whole story, though. An ADU has to meet local zoning, fit your lot, and work as a self-contained home. Our architects are licensed, and we understand local zoning codes, building regulations, and permit requirements. We make sure mother-in-law suites and ADUs comply with local zoning. In a feasibility study, we can review height, floor area, setbacks, and critical areas before you commit to a design.

What does it cost to build an ADU?

We can't give a single construction figure, because the cost depends on the unit's size, its finishes, the site conditions, and whether you are converting an existing space or building new. Our schematic design drawings are prepared so that a builder or general contractor can give a preliminary rough-order-of-magnitude estimate. We recommend working with a general contractor for cost estimating. We also help you weigh financial and regulatory factors early, so the design and budget stay aligned. Contact us to talk through your project.

How long does an ADU design project take?

Timing depends on the scope of your unit, how clear your goals are, and how your local jurisdiction handles reviews. The firm states that design and permitting typically take 4–6 months for clients with a clear vision and a defined program, depending on the jurisdiction. If you are still deciding what you want, we can produce several floor plan and 3D options to help you choose. Construction time depends on your builder and the unit itself. Get in touch and we can talk about what to expect for your property.

How much does an architect charge for an ADU?

The firm states that its fees typically range between 5% and 15% of total construction cost. We tailor our fee approach to the project's complexity, site conditions, and the level of service you need. A conversion that works within an existing structure is a different job from a new detached unit on a tricky lot. Services are tailored project by project. We offer a free consultation covering your vision, your site, your budget, and what is possible. That gives you a clear picture of the fee before you commit.

Why hire an architect for your ADU?

A small unit has to do a lot in a small footprint. It needs a kitchenette, a bathroom, and living space that feel comfortable, and it has to follow zoning rules that can shape what you are allowed to build. We design ADUs meant to blend into existing homes and neighborhoods. We also handle permit paperwork, which streamlines the application and reduces the risk of rejections. If you are building to rent, downsize, or house family, our design and documentation support those goals. We can also provide detailed documentation to help you meet construction loan requirements.

Good design goes a long way.

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