DADU & ADU Construction for Seattle & the Eastside

Costs vary based on the size, layout, features, and complexity of the project, but most DADUs and ADUs in the Seattle and Eastside areas start around $350,000 to $500,000+. High end projects with custom finishes, energy upgrades, or complex site requirements often exceed this range. At Emerald City Construction, we provide detailed pricing during pre construction so you know exactly what to expect before you begin.

Most DADUs and ADUs take 8 to 14 months from first planning conversations to move in. This timeline can shift depending on permitting, site conditions, engineering needs, and the level of customization. Our process helps keep your project organized and on track so you can plan confidently.

Yes. Both Seattle and Eastside cities require building, electrical, mechanical, and sometimes land use permits for DADUs and ADUs. Requirements vary by jurisdiction, especially around setbacks, height limits, and parking. We handle all permitting on your behalf and guide you through the steps so there are no surprises.

Homeowners are gravitating toward energy efficient layouts, open concept living spaces, vaulted ceilings, flexible rooms, sustainable materials, and modern Pacific Northwest architecture. Many families are choosing warm wood tones, smart home features, quartz surfaces, and outdoor living spaces to bring comfort and durability into compact square footage.

A DADU is a detached unit such as a backyard cottage, while an ADU is located within or attached to the main home, such as a basement apartment or converted garage. DADUs offer maximum privacy and flexibility, while attached ADUs make use of the existing structure. We help you decide which option best fits your property, goals, and budget.

Think about who will use the space, how long term your plans are, and what level of independence you want the unit to have. Consider private entries, kitchen or kitchenette needs, accessibility features, storage, daylight access, and parking. Our team can help creates a thoughtful and efficient layout that makes the most of every square foot.

Costs are shaped by size, site conditions, utilities, excavation, drainage, foundation needs, structural engineering, finishes, appliances, and energy performance upgrades. Locations with tight access or older homes may require additional work. We outline all costs clearly during design so that your investment stays aligned with your goals.

Yes. Because most work happens outside or within a separate portion of the home, homeowners can usually stay put throughout the build. We work hard to maintain a clean and safe environment, keep noise predictable, and limit disruptions to your daily routine.

Great design is key. Features like built in storage, open layouts, tall ceilings, large windows, and multi purpose furniture make compact spaces feel larger. We love partnering with local designers and architects to find creative ways to maximize smaller spaces.

Most single family lots in Seattle are now eligible, but requirements differ by zoning, lot size, and existing structures. Some regulations also vary between Seattle and Eastside jurisdictions. We review your property early in the process to determine feasibility, setbacks, utility access, and the best placement for your unit.

Yes. Many homeowners build ADUs or DADUs for long term rental income or short term stays, depending on local rules. Seattle has specific regulations for short term rentals, so checking local laws for your specific property can confirm your DADU/ADU usage.