How long does ADU construction take?

Most detached ADU projects take 4-8 months from permit submission to final inspection, depending on size and complexity.

Do you handle the ADU permits?

Yes — permit management is part of our scope. We know Seattle ADU permitting well.

What does an ADU typically cost?

Detached ADUs in Seattle typically range from $250K-$450K+ depending on size, finishes, and site conditions. We provide detailed estimates after a site visit.

Can I rent out my ADU?

Yes. Seattle allows ADU rentals and we can build to rental-ready standards.

What's the difference between an ADU and a DADU?

An ADU (accessory dwelling unit) is a general term that includes both attached and detached units. A DADU (detached accessory dwelling unit) is specifically a standalone structure separate from the primary home — a backyard cottage or carriage house. Seattle has specific permitting rules for each.

ADU Construction

ADU construction, permit to punch list

Accessory dwelling units built from permit to punch list — detached, attached, and DADU options for Seattle lots.

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I'd heard ADU permitting in Seattle was a nightmare and honestly almost didn't move forward. Marco walked me through the land use, building, and inspection process at the start and managed every step himself — I never had to follow up on anything. The build came in on schedule, passed final inspection the first attempt, and it rented out the first week we listed it.

Jordan P.

Phinney Ridge

What we do

ADU construction services

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Detached ADUs: Standalone backyard cottages, carriage houses, and garden suites designed and built as complete living spaces. We handle everything from foundation and framing through kitchen, bath, HVAC, and final inspection under one contract.
Attached ADUs: Ground-floor or above-garage units connected to the primary home through shared wall construction. Attached ADUs often allow for plumbing and electrical sharing with the main house, which can reduce overall project cost compared to a fully detached unit.
Permit management: Full Seattle ADU permitting including land use review, building, mechanical, electrical, and plumbing permits. ADU permitting involves multiple city departments — we've done this enough to know the sequence and avoid the common delays.
Site work & utilities: Foundation, drainage, utility connections, and lot grading for the new structure. Proper site prep is what prevents drainage issues after the ADU is built — we don't skip steps on the work that gets buried.

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Featured Previous Work

Phinney Ridge Backyard ADU

A 400 sq ft detached ADU in Phinney Ridge — full kitchen, full bath, sleeping loft, and a covered deck, permitted and built by one team.

Their Story

Underutilized backyard on a Phinney Ridge lot — homeowners wanted rental income and a space for family guests.

Designed and built a 400 sq ft detached ADU with a sleeping loft, full kitchen, full bath, and covered deck — managed permitting through the City of Seattle.

Read full case study

Overview

Timeline: 6 months
Completed: August 2025
Location: Phinney Ridge

Our Process

Consultation & Site Visit

We review your goals, space, and budget and answer initial questions.

Estimate & Scope Review

You receive a clear, written estimate with defined scope and expectations.

Build Phase

We coordinate trades, manage permits if required, and keep the site clean and organized.

Final Walkthrough

We review details with you and make sure everything is completed properly.

Frequently asked questions

Can't find the answer you're looking for? Give us a call .

How long does ADU construction take?: Most detached ADU projects take 4-8 months from permit submission to final inspection, depending on size and complexity.
Do you handle the ADU permits?: Yes — permit management is part of our scope. We know Seattle ADU permitting well.
What does an ADU typically cost?: Detached ADUs in Seattle typically range from $250K-$450K+ depending on size, finishes, and site conditions. We provide detailed estimates after a site visit.
Can I rent out my ADU?: Yes. Seattle allows ADU rentals and we can build to rental-ready standards.
What's the difference between an ADU and a DADU?: An ADU (accessory dwelling unit) is a general term that includes both attached and detached units. A DADU (detached accessory dwelling unit) is specifically a standalone structure separate from the primary home — a backyard cottage or carriage house. Seattle has specific permitting rules for each.

We built our business on clear communication and quality work

Home remodeling works best when expectations are clear and communication is consistent. We focus on being responsive, transparent about scope and pricing, and respectful of your home from start to finish — so there are no surprises along the way.

Clear, upfront estimates

You'll receive a detailed estimate that outlines scope, materials, and next steps, so you know exactly what to expect before work begins.

Licensed, insured, and code-compliant

All work is performed by a licensed and insured general contractor and built to meet current codes and local requirements.

Clean, professional job sites

We work in occupied homes and condos and take care to keep the site organized, safe, and respectful of your space.

Seattle's Trusted Residential Contractor

Your No-Nonsense Partner in Exceptional Construction. Licensed & Insured.

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