Working with No.7 has been an absolute pleasure. All work was done on time and on budget. All of the workers were not only professional but went out of their way to be helpful and kind. When we had questions or needed suggestions someone always took the time to help us out. I gave used this company for 2 projects and hopefully a third in the future. I would highly recommend to anyone.
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No 7 Development builds accessory dwelling units and detached accessory dwelling units for homeowners across Mount Vernon, Burlington, Anacortes, Oak Harbor, Bellingham, and throughout Skagit, Whatcom, and Island County.
An ADU is one of the most valuable investments a Northwest Washington homeowner can make — adding usable square footage, housing for family members, or rental income potential without the cost and complexity of buying a new property. Done right, it looks intentional, functions well, and adds lasting value to your property.
What We Build
We build all three main types of ADUs depending on your property and goals. Detached ADUs are standalone backyard cottages built separately from your main home — the most flexible option and typically the most valuable. Attached ADUs connect directly to your existing home as a self-contained unit with its own entrance. Garage conversion ADUs transform an existing garage into finished living space — often the most cost-effective path when the structure is already in place.
Permitting in Skagit and Surrounding Counties
ADU permitting requirements vary significantly between jurisdictions in Northwest Washington. What's allowed in unincorporated Skagit County differs from city of Mount Vernon requirements, which differ again from Island County or Whatcom County rules. Setbacks, size limits, owner-occupancy requirements, and utility connection rules all vary. We know these jurisdictions and handle the permitting process so you're not navigating it alone.
What Does an ADU Cost?
ADU project costs vary widely depending on type, size, site conditions, and finish level. A garage conversion and a fully detached 800 square foot cottage are very different scopes. We'll give you an honest number after understanding your specific property and goals — not a ballpark that bears no resemblance to the final invoice.
We've built ADUs in Mount Vernon, Anacortes, Oak Harbor, Burlington, and across the islands and valleys of Northwest Washington. If you're considering an ADU on your property, contact us for a free consultation.
Reviews
Take a look at what your neighbors are saying about us.
Areas We Serve
- Mount Vernon, WA
- Skagit County, WA
- Island County, WA
- Whatcom County, WA
- Snohomish County, WA