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Seattle ADUs, Built the Right Way
A smooth, guided design–build process for ADUs, DADUs, and backyard offices — from feasibility to final inspection.
About Our ADU Services in Seattle
An ADU (Accessory Dwelling Unit) is a fully independent living space on your property — perfect for rental income, family housing, or simply adding more room without leaving the neighborhood you love. In Seattle, ADUs can be attached to your home (AADUs), built as a detached backyard cottage (DADU), or created by converting a garage or finished basement.
We design and build ADUs that fit your lot, your home, and your goals. Our team manages everything — feasibility, architectural design, engineering, SDCI permitting, and construction — so your ADU comes together smoothly from the first idea to move-in day. Whether you’re planning a rental unit, a guest cottage, or a space for family, we help you create something functional, beautiful, and built to Seattle’s requirements.
What You Can Build With Us
- Attached ADUs (AADUs): Lower-level or side-addition units with private entrances.
- Detached ADUs (DADUs): Backyard cottages up to 1,000 sq ft for rentals or multigenerational living.
- Garage Conversion ADUs: Transform an existing garage into a legal, efficient living unit.
- Basement ADUs: Finished lower-level spaces ideal for rental or extended family living.
Why Homeowners Choose ADUs
- Rental income to offset mortgage costs or create long-term revenue.
- Space for family without buying a second property or leaving Seattle.
- Increased property value with a fully permitted, livable unit.
- Flexible use — guest cottage, teen suite, workspace, or future housing.
Why Seattle Homeowners Choose Us
Seattle ADU Experts
We understand Seattle’s zoning, SDCI permitting, lot requirements, and build standards. Our team guides you through everything so your ADU is designed and approved the right way.
Full Design–Build Service
From feasibility and architectural design to engineering, permits, and construction, we manage the entire ADU process under one team for a smooth, stress-free experience.
Quality Builds, Transparent Process
You get clear communication, up-front pricing, and thoughtful craftsmanship—whether it’s a DADU, basement ADU, garage conversion, or attached addition.
What Seattle Homeowners Say About Our ADU Builds
Seattle ADU FAQ
Do you handle the entire ADU project or just the build?
We’re a full design–build team. We handle feasibility, architectural design, engineering, SDCI permitting, and construction, so you don’t have to coordinate multiple vendors.
Can you help me figure out what type of ADU fits my property?
Yes. Our feasibility review looks at zoning, setbacks, buildable area, and utilities, then recommends whether a DADU, attached ADU, basement ADU, or garage conversion is the best fit for your lot and goals.
Do Seattle ADUs usually require utility upgrades?
Often they do. Depending on your existing electrical capacity, sewer line, and water service, the city may require upgrades. We evaluate this up front and include any required utility work in your plan and budget.
How do you help keep ADU projects on budget?
We start with a detailed, line-item estimate and review it with you before finalizing design. During the build, we provide regular updates and approvals on any changes so you’re always clear on scope and cost.
Can you match my home’s style or build something more modern?
Yes. We can echo your home’s existing architecture or go in a more modern direction. Our design team works with you on materials, rooflines, and details so the ADU feels intentional on your property.
Can I rent out my ADU in Seattle?
Yes. Seattle allows ADUs and DADUs to be rented long term (30+ days). Many of our clients build ADUs specifically for rental income, future flexibility, or to improve resale value.
What’s the typical timeline for designing and building an ADU?
Most ADU projects take about 6–12 months from design to move-in, including design and engineering, permitting (SDCI in Seattle) and construction. We’ll give you a project-specific timeline once we’ve reviewed your property and ADU type.
What is the maximum size for an ADU in Seattle?
Seattle allows a range of ADU and DADU sizes depending on your zoning, lot size, and whether the unit is attached or detached. In many cases, detached ADUs can go up to around 1,000 square feet, but the exact limit is determined by your property’s zoning and lot coverage rules. We verify all size and setback limits as part of our feasibility study.
Do I need off-street parking for an ADU in Seattle?
In many Seattle neighborhoods, an additional off-street parking space is not required for an ADU, especially in areas with good transit access. The details depend on your specific zoning and location. We’ll review the applicable parking standards for your property and include them in your design and permit set.
Will adding an ADU increase my property value?
In most cases, a well-designed, fully permitted ADU or DADU adds significant value to your property by creating flexible, rentable, or multi-generational space. Many owners use ADUs for long-term rentals, guest suites, or home offices, which can help offset the cost of construction over time.
