ADU Construction in Seattle
Backyard cottages that earn $2,000–$3,200/mo in rent, or a home for family • Design, permits and construction from one team • Free site assessment
Add a Second Home to Your Property
An accessory dwelling unit turns unused backyard, garage or basement space into a legal, independent home that pays you back: a one-bedroom cottage in Seattle rents for about $2,000–$2,500 a month, or houses parents or adult children instead of a separate apartment. Washington now allows up to two ADUs on most residential lots, and Seattle offers pre-approved cottage plans that cut permit time to weeks.
TopVolk Construction LLC handles the whole project: site assessment, drawings, SDCI or city permits, utility connections, construction and every inspection through final approval. One contractor, one written timeline, and $100 back for every day we run past it.
ADU Types We Build
Detached, attached or converted — we help you pick the option that fits your lot and budget
Detached ADU (DADU)
Backyard cottage
A stand-alone unit in your backyard with its own entrance, kitchen and bathroom. Up to 1,000 sq ft in Seattle. The most private option and the strongest rental product.
Attached ADU (AADU)
Addition or basement
A separate unit built onto your house or carved out of an existing basement or level. Shares a wall with the main home but has its own locking entrance and full kitchen.
Garage Conversion
Existing structure
Turn a detached or attached garage into living space. Reuses the foundation, roof and electrical feed, so it is usually the fastest and lowest-cost route to a legal unit.
Basement ADU
Below-grade unit
Finish and separate a basement into an independent apartment: egress windows, a separate entry, waterproofing, a kitchen and a bathroom. Ideal for older Seattle homes on sloped lots.
ADU Models & Starting Prices
Four proven configurations for Seattle lots — each one adapted to your parcel, setbacks and finish level
Studio DADU
Compact backyard cottage
The smallest footprint that still works as a full home: open living and sleeping area, a real kitchen and a full bathroom. Fits on most Seattle lots without giving up the whole yard.
- ✓Open studio layout
- ✓Full kitchen & bathroom
- ✓Mini-split heating & cooling
- ✓Private entrance & porch
Ideal for: Rental income, home office, guest suite
Most PopularOne-Bedroom DADU
Our most requested plan
A separate bedroom, a living room with a sliding door onto a small deck, and a kitchen with full-size appliances. The layout renters and family members ask for most.
- ✓Separate bedroom
- ✓Living room with deck access
- ✓Full kitchen with pantry
- ✓Washer/dryer closet
Ideal for: Long-term rental, parents, adult children
Two-Bedroom Cottage
Room for a family
One-and-a-half stories with a covered porch and a loft-style second bedroom. Up to the 1,000 sq ft Seattle allows for a detached unit — a real second home on your property.
- ✓Two bedrooms
- ✓Covered front porch
- ✓Full kitchen & laundry
- ✓Option for a second bathroom
Ideal for: Multigenerational living, family rental
Garage Conversion
Fastest path to a rental unit
Your existing garage already has a foundation, a roof and a power feed. We insulate, add plumbing, replace the garage door with a window wall and finish it as a code-compliant dwelling unit.
- ✓Uses existing structure
- ✓New insulation & windows
- ✓Kitchenette & bathroom
- ✓No new foundation needed
Ideal for: Budget-conscious owners, quick rental
Concept renderings and planning figures for the greater Seattle area. Starting prices are preliminary; final pricing depends on site conditions, utility connections and finishes and is set after a free site assessment and a signed scope-of-work agreement.
Turn Your Backyard Into Income
A permitted ADU is the one home improvement that pays you back every month
Long-term rental income
A one-bedroom backyard cottage in Seattle rents for roughly $2,000–$2,500 a month, a two-bedroom for $2,600–$3,200. That is $24,000–$38,000 a year from space you already own, every year, for as long as you hold the property.
Live in the ADU, rent the main house
The fastest way to cut your housing cost: move into the cottage and rent out the 3-bedroom house at full market rent. Many Seattle homeowners cover most of their mortgage this way.
Housing for family instead of rent
Parents, adult children or a caregiver get a private home with a full kitchen and bathroom on your lot. Compared with a separate apartment or assisted living, the savings run into thousands of dollars a year.
A second dwelling raises what your property is worth
A permitted, inspected ADU is a second legal home on the parcel. Appraisers count it, and buyers pay for the income it produces. Washington now allows two ADUs per lot, so the option to build is itself part of your property’s value.
| Configuration | Build from | Est. rent / mo |
|---|---|---|
| Studio DADU | $180,000 | $1,600–$1,900 |
| One-Bedroom DADU | $240,000 | $2,000–$2,500 |
| Two-Bedroom Cottage | $300,000 | $2,600–$3,200 |
| Garage Conversion | $95,000 | $1,500–$1,800 |
ADU Income Calculator
Pick a configuration and adjust the rent to your neighborhood
Seattle-area estimate for this size: $2,000–$2,500/mo
Gross rent against the starting build price of $240,000. Excludes financing, vacancy, taxes and maintenance. Starting prices are preliminary and confirmed after a free site assessment.
Seattle Pre-Approved DADU Plans
Build from the city's catalog of pre-reviewed backyard cottage designs and skip months of permitting
Skip design fees
Plans are already drawn and reviewed — you buy the plan set instead of paying for architecture from scratch.
Faster permits
Seattle SDCI issues permits for pre-approved DADUs in about 2–6 weeks instead of a full plan review.
Code compliance built in
Structural, energy and life-safety reviews are already done, so there are fewer resubmittals.
Adapted to your lot
We handle the site plan, setbacks, utility routing and foundation design that still have to be done for every parcel.
| Custom Design | Pre-Approved Plan | |
|---|---|---|
| Design & architecture | Custom drawings for your lot | Ready plan set from the city catalog |
| Permit review | 6–12 weeks | 2–6 weeks |
| Total timeline | 6–9 months | 4–7 months |
| Code compliance | Reviewed during permitting | Pre-reviewed by SDCI |
15% OFF All Labor
Book your renovation this week and save on labor costs.
Materials are billed separately and are not included in the discount.
Your ADU in 4 Steps
From the first site visit to the certificate of occupancy
Free Site Assessment
Vladislav visits your property, checks lot size, setbacks, utility access and the condition of any structure you want to convert. You get a written preliminary estimate — no charge.
Design & Permits
Choose a Seattle pre-approved DADU plan or a custom design for your lot. We prepare the drawings, submit to SDCI or your city, and handle plan-review comments until the permit is issued.
Construction
Foundation, framing, plumbing, electrical, insulation, drywall and finishes — one team from start to finish. Construction typically runs 10–16 weeks after the permit is issued.
Inspection & Handover
We coordinate every city inspection through final approval, then walk the unit with you before handover. Deadline is in the contract: we pay $100 for every day past it.
Every ADU Includes
One line-item estimate covers the whole unit — no surprise add-ons between the drawings and the keys.
Starting Prices
- Studio DADU≈ 400 sq ft · Studio · 1 bathRents ≈ $1,600–$1,900/mofrom $180,000
- One-Bedroom DADU≈ 600 sq ft · 1 bed · 1 bathRents ≈ $2,000–$2,500/mofrom $240,000
- Two-Bedroom Cottage≈ 800 sq ft · 2 bed · 1–2 bathRents ≈ $2,600–$3,200/mofrom $300,000
- Garage Conversion≈ 400–500 sq ft · Studio / 1 · 1 bathRents ≈ $1,500–$1,800/mofrom $95,000
Preliminary planning figures. Permit and plan-review fees are passed through at cost. A separate water/sewer service line, when you choose one, is quoted separately.
Why Build Your ADU with TopVolk Construction LLC?
Licensed & Insured
Washington State licensed contractor with full insurance coverage. Every unit is permitted and inspected.
Deadline in the Contract
A written timeline before work starts. We pay $100 for every day past the agreed deadline.
Direct Communication
Work directly with Vladislav — no middlemen, clear expectations, honest recommendations on what fits your lot.
One Team, Start to Finish
Design, permits, foundation, framing, plumbing, electrical and finishes — 100+ projects completed since 2023.
Vlad and his team did an amazing job! They built our deck in just 3 days—no issues at all. Communication was easy, and Vlad helped us choose right deck planks. Installation was quick and flawless. Highly recommend!
Really happy with the service! Vlad was easy to communicate with and helped us to find the best garage door opener. The installation was quick and he did a perfect job. A few months later, I had a question and he came by the same day - even on a weekend. That kind of follow-up is rare these days!
Vlad replaced a bathroom exhaust fan and gave me a reasonable quote up front with no hidden fees. While replacing the fan, he discovered a plumbing vent issue causing mold. He fixed the pipe and treated the mold at a reasonable cost. I really appreciate his honesty!
Outstanding work done by Vlad and team for our home cabinet/living room interior work. Very professional and reasonable charges. Love the service.
We hired TopVolk for a full kitchen remodel and couldn't be happier. From the initial consultation to final walkthrough, Vlad was professional and attentive to every detail. The result exceeded our expectations!
Excellent bathroom renovation! Vlad completed the project on time and on budget. His attention to detail and craftsmanship is outstanding. We'll definitely hire him again for future projects.
ADU Questions, Answered
How much does it cost to build an ADU in Seattle?
A detached ADU in the greater Seattle area typically starts around $180,000 for a 400 sq ft studio and $240,000–$330,000 for a 600 sq ft one-bedroom, with larger two-bedroom cottages from about $300,000. Garage conversions start near $95,000 because the foundation and roof already exist. Prices depend on site conditions, utility connections and finish level. Every estimate through this website is preliminary; final pricing is set after a free in-person site assessment and a signed scope-of-work agreement. Call (206) 591-1096 to schedule.
How long does an ADU project take from start to move-in?
Design and permit preparation start within two weeks of signing. Seattle SDCI plan review takes about 2–6 weeks for a pre-approved DADU plan and 6–12 weeks for a custom design; construction then runs 10–16 weeks. Four to seven months end-to-end is realistic for most lots. You get a written timeline before work starts, and TopVolk Construction LLC pays $100 for every day past the agreed deadline.
How much rental income can a Seattle ADU earn?
Based on 2026 Seattle rent benchmarks, a new detached studio rents for about $1,600–$1,900 a month, a one-bedroom cottage for $2,000–$2,500, a two-bedroom for $2,600–$3,200, and a converted garage studio for $1,500–$1,800. A one-bedroom unit built for $240,000 therefore returns roughly $24,000–$30,000 a year in gross rent, a simple payback of eight to ten years, after which the income is yours for as long as you own the home. Actual rent depends on neighborhood, finishes and parking.
Does an ADU increase my home’s value?
A permitted ADU is a second legal dwelling on your parcel: appraisers count its square footage and buyers pay for the rental income it produces, so a finished unit adds to what the property is worth as well as generating cash flow while you own it. The exact premium depends on your neighborhood and the unit, so we do not promise a fixed percentage. What we can guarantee is a fully permitted, inspected unit with a certificate of occupancy, which is what makes the value real to a lender or a buyer.
How many ADUs can I build on my lot in Washington?
Washington House Bill 1337, in force statewide since mid-2025, requires cities to allow up to two accessory dwelling units on a residential lot — for example one attached and one detached — without an owner-occupancy requirement, and without off-street parking when the lot is within a half mile of a major transit stop. Local codes still set height, setbacks and lot coverage, so we confirm what fits during the free site visit.
What size ADU is allowed in Seattle?
In Seattle a detached ADU can generally be up to 1,000 sq ft of floor area, with height limits that depend on the roof form and lot width. Side and rear setbacks are typically 5 feet, and single-family zones cap total lot coverage. Lots under about 4,000 sq ft face tighter math, which is why we run the numbers with your actual parcel data before drawing anything.
Do you handle the ADU permit?
Yes. We prepare the drawings, submit the application to Seattle SDCI or the permit authority in your city — Bellevue, Kirkland, Tacoma, Everett and others — respond to plan-review comments and schedule every inspection through final approval. Permit and plan-review fees charged by the jurisdiction are passed through to you at cost, with no markup.
What are Seattle pre-approved DADU plans, and can I use one?
The City of Seattle keeps a catalog of detached ADU designs that SDCI has already reviewed for structural, energy and building-code compliance. Using one skips most of the design work and shortens permit review to roughly 2–6 weeks. The plans apply within the City of Seattle; outside city limits we design to your city or county code under the standard review process. We still prepare the site plan, foundation design and utility routing for your specific lot.
Can I rent out my ADU?
Yes. Long-term rental of an ADU is allowed in Seattle and across Washington, and HB 1337 removed the owner-occupancy requirement statewide. Short-term rental rules vary by city and may require a separate license. We build every unit as a fully independent dwelling — private entrance, full kitchen and bathroom — so it can be rented, used by family or sold with the property.
Does the ADU need its own water, sewer and electrical service?
Not always. Many Seattle ADUs share the main house’s water and sewer line and get a sub-panel from the existing electrical service. A separate service line adds roughly $8,000–$18,000 depending on trench distance to the main, but makes the unit fully independent for financing or a future sale. We price both options in your estimate so you can choose.
Can you convert my garage or basement into an ADU?
Yes. Garage and basement conversions are the lowest-cost route to a legal unit because the structure already exists. The work usually covers insulation, egress windows, a separate entrance, plumbing for a kitchen and bathroom, an electrical upgrade and, for basements, waterproofing. We confirm ceiling height, foundation condition and moisture before quoting.
How do homeowners pay for an ADU?
Most homeowners fund an ADU with a home-equity line of credit, a cash-out refinance or a construction/renovation loan; some combine that with the expected rental income. We are a construction company, not a lender, but the detailed written estimate and timeline we provide are what lenders ask for when underwriting the project.
Is TopVolk Construction LLC licensed and insured for ADU construction?
Yes. TopVolk Construction LLC is a fully licensed and insured construction contractor in Washington State, serving the greater Seattle area since 2023 with more than 100 completed projects across King, Snohomish and Pierce counties. Construction work is covered by a written workmanship warranty specified in your project agreement.
Ready to Build Your ADU?
Free site assessment, written preliminary estimate, no obligation.
ADU Construction Service Areas
We build ADUs throughout the greater Seattle area
King County(41 cities)
Snohomish County(15 cities)
Pierce County(19 cities)
Kitsap County(5 cities)
Whatcom County(4 cities)
Skagit County(4 cities)
Island County(2 cities)
Clallam County(3 cities)
Jefferson County(1 cities)
Pacific County(1 cities)
Mason County(1 cities)
Chelan County(2 cities)
Douglas County(1 cities)
Kittitas County(2 cities)
Other Services We Offer
General Contracting
Comprehensive construction project management from planning to completion. Licensed contractor for residential and commercial projects.
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Bathroom Remodeling
Transform your bathroom into a modern, functional space. From small updates to complete renovations with premium fixtures and finishes.
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Kitchen Remodeling
Complete kitchen renovation services including cabinets, countertops, appliances, and layout optimization for maximum functionality.
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Deck & Patio Construction
Professional deck construction using premium materials. We design and build custom decks that enhance your outdoor living space.
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Basement Finishing
Transform your basement into a functional living space. Complete basement remodeling with waterproofing and insulation.
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Flooring Installation
Expert installation of hardwood, laminate, tile, and vinyl flooring. Professional preparation and precise installation.
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Interior & Exterior Painting
Complete painting services for homes and commercial buildings. High-quality paints and professional preparation.
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Tile Installation
Professional tile installation for floors, walls, backsplashes, and showers. Custom tile work with precision.
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Carpentry
Custom carpentry services including trim work, cabinetry, and built-in furniture.
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Window Installation
Energy-efficient window installation and replacement. Vinyl, wood, and composite windows.
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Door Installation
Interior and exterior door installation. Entry doors, patio doors, and garage doors.
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Fence Installation
Custom fence installation for privacy, security, and aesthetics. Wood, vinyl, and metal fencing.
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Drywall Installation
Professional drywall installation, repair, and finishing. Smooth walls and ceilings for any project.
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Garage Construction
New garage construction and detached garage building. Complete garage construction services.
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Handyman Services
General handyman services for small repairs, maintenance, and home improvement projects.
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Power Washing
Exterior cleaning services including power washing for decks, siding, driveways, and patios.
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Insulation
Energy-efficient insulation installation for walls, attics, and crawl spaces.
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