TownhomesModern Rowhomes
West Seattle
Detached ADU
DADU
Permitting
A second home in your backyard — permitted cleanly through SDCI, from feasibility to final inspection.
A detached accessory dwelling unit is the fastest way most Seattle homeowners add real, rentable square footage without leaving their lot. Since the city's 2019 reforms and Washington's 2023 ADU law, the rules strongly favor building — but the permit path still rewards getting the zoning, design standards, and utility details right the first time. That's the part we own.
What's included
- Lot feasibility & buildable-envelope study
- Pre-approved plan evaluation
- Full SDCI construction permit drawings & forms
- Side-sewer / utility connection coordination
- Energy-code documentation
- Correction responses through to issuance
01
What Seattle actually allows now
The owner-occupancy requirement is gone, parking mandates have largely been removed, and most single-family lots can carry both an attached and a detached unit. We confirm exactly what your parcel supports before any drawing begins.
- No owner-occupancy requirement
- Up to two ADUs on most standard lots
- Parking minimums removed in most of the city
- Backed by Washington's 2023 statewide ADU law
02
The design standards that decide your envelope
A DADU lives or dies on height, setbacks, lot coverage, and floor-area ratio. We model your buildable envelope against the code so the design your architect or our pre-approved plan set produces sails through review instead of bouncing back.
- Maximum height & roof-form rules
- Rear/side setbacks and separation from the main house
- Lot coverage and FAR limits
- Tree protection and green-factor where triggered
03
The pre-approved plan shortcut
Seattle maintains a library of pre-approved DADU plan sets that skip a large chunk of structural and architectural review. When a standard plan fits your lot, it is the single biggest lever on both cost and timeline — and most expediters never bring it up. We will tell you honestly whether it fits.
Built & permitted
DADUs we've
permitted & built.
Real backyard cottages we designed, permitted through Seattle SDCI, and built — every photo is our own. Open any project for the full set, then let's map the same permit path for your lot.
Real projects
Permitted &
built in Seattle.
Every home here we designed, permitted, and built ourselves — our own developments across the Seattle area under Seattle Modern Buildings. All photos and details are genuinely ours, never stock. Drag or swipe to explore.
Townhomes
New HomeSkyline Vantage
Seattle
New HomeCedar-Entry New Build
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New HomeRooftop Deck & Spa
Seattle
TownhomesInfill Townhomes
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DADUDetached Backyard Home
Seattle
ADURear Yard & Lower-Level Suite
Seattle
InteriorLight-Filled Open Kitchen
Seattle
TownhomesModern Rowhomes
West Seattle
New HomeSkyline Vantage
Seattle
New HomeCedar-Entry New Build
Seattle
New HomeRooftop Deck & Spa
Seattle
TownhomesInfill Townhomes
Seattle
DADUDetached Backyard Home
Seattle
ADURear Yard & Lower-Level Suite
Seattle
InteriorLight-Filled Open Kitchen
Seattle
DADU Permitting — questions
How big can my DADU be?
Size is driven by your lot's coverage and FAR limits plus height and setback rules — not a single flat number. We calculate your specific maximum during the feasibility step so you design to what's actually permittable.
Can I rent it out?
Yes. With owner-occupancy requirements removed, a permitted DADU can be rented long-term. We make sure it's a legal, separately-addressed dwelling so financing and insurance hold up.
Ready to start your
DADU permit?
Tell us about your lot and project. We'll map the permit path and timeline before you spend on drawings.
Start Permit Review