ADUs & DADUs
Backyard Cottages, Attached Suites & Basement ADUs, built for Seattle lots.
Detached cottages, attached suites, and basement apartments. Designed, permitted, and built end to end across Seattle, the Eastside, and greater Puget Sound.
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What kind of project?
What We Build
Four ADU types. One builder.
Whether you're adding a backyard cottage for rental income, finishing a basement for an aging parent, or expanding your home with an attached suite, MNBE handles every ADU configuration Washington's HB 1337 expansion allows.
Detached ADUs (DADUs)
Standalone backyard cottages, typically 800 to 1,200 sq ft. The most popular ADU type for rental income and multigenerational privacy.
Up to 1,200 sq ft
Attached ADUs
Connected to the main house through a shared wall, addition, or breezeway. Ideal when lot setbacks make a detached unit difficult.
Up to 1,000 sq ft
Basement ADUs
Conversion of an existing basement into a legal accessory dwelling, with a separate entrance, full kitchen, and code-compliant ceiling height.
Up to 800 sq ft typical
Backyard Cottages
The Pacific Northwest term for a detached ADU built as a true second small home. Common in Seattle's pre-approved DADU program.
Up to 1,000 sq ft
Why MNBE
The Eastside ADU expertise homeowners hire when permits matter.
ADU code is the most-changed slice of WA building law in the past three years. We track every revision so your project clears without cycling.
HB 1337 zoning fluency
Washington's 2023 ADU expansion changed setback rules, parking minimums, and owner-occupancy requirements city by city. We know which rules apply where.
Pre-approved plan integration
Seattle's pre-approved DADU program can shave months off permitting. We've built from these plans and know which ones fit which lots.
In-house permitting team
Submittals, plan-check corrections, inspections. Handled by us, not subbed out. One contact. One timeline. One responsible party.
How It Works
Three stages, one team, one fixed price.
- 1
Plan
Free site visit. We walk the lot, run the zoning code for your city, and tell you what is realistically buildable before drawings start.
- 2
Permit
Permit-ready drawings, submittal, and shepherding. We manage every plan-check correction through SDCI or your Eastside city.
- 3
Build
Foundation through finish, supervised by Aaron personally. Weekly homeowner updates, full inspections, fixed-price contract.
Recent ADU Projects
ADUs we've delivered across the Eastside.
Every project below was permitted, supervised, and delivered by the MNBE team. Walkthrough videos and full project pages coming soon.
Frequently Asked
The ADU questions Seattle homeowners ask before they hire.
Real answers from a real builder. If you don't see your question here, call us. We answer the phone.
Still have questions?
We answer the phone Monday through Saturday. Two minutes on the call usually gets you further than an hour online.
An ADU (Accessory Dwelling Unit) is the umbrella term for any independent living unit on the same lot as a primary home. A DADU (Detached ADU) is one specific type, a freestanding structure separate from the main house. Other ADU types include attached ADUs (connected to the main home), basement ADUs (conversions), and junior ADUs (smaller interior conversions, usually under 500 sq ft).
From signed contract to certificate of occupancy, plan on 6 to 10 months for a typical detached ADU in Seattle on Aaron's schedule. That breaks down roughly as 3 to 5 weeks for design, 2 to 4 months for permits at Seattle DCI, and 3 to 5 months of construction. Pre-approved plans and faster Eastside cities like Redmond can compress this further. Aaron's crews build faster than the regional average and we hold the schedule we put in writing.
Every ADU project is bid as a fixed-price contract after one free site visit and a design consultation. We don't publish per-square-foot pricing because soil conditions, lot setbacks, utility tie-ins, finish level, and design complexity all move the number meaningfully, and the average doesn't match the actual job we'd quote you. Walk us through what you have in mind and we'll come back with a written bid line by line, including permits, design, finishes, and final landscaping.
Both are allowed in Seattle and most Eastside cities, but specific rules vary. Seattle requires short-term rental operators to register and limits non-primary-residence STRs. Long-term rentals (30 days or more) are generally unrestricted. Bellevue and Kirkland have their own short-term rental regulations. We'll walk you through the specific rules for your city during the consultation.
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Thank you for considering MNBE for your project. We'll get back to you during normal business hours, Monday through Saturday.