PILLAR_01
Fixed-price contracts
We walk every lot before quoting and lock the number in writing. No allowances, no open-ended estimates, no surprise change orders mid-build.
Held to contract: 96% of jobs in 2024
ESTABLISHED 2012 · SEATTLE, WA
BUILT FOR
PERFORMANCE.
Design-build ADUs and additions across the Puget Sound. Engineered construction, fixed-price contracts, finished on time.
ADUs Delivered
In Business
Liability Coverage
Licensed & Bonded
WA Lic # GOLDESA747LZ$2M Liability Insured$25K Contractor BondBBB MemberEnergy Star Builder
Capabilities
SPEC_01 / CORE_SERVICESSPEC_02 / FULL BUILD SCOPE
The complete
contractor stack.
ADUs are our specialty — but our crew, license, and engineering reach across the entire Puget Sound construction stack. 38+ services under one roof.
SPEC_03 / NEW CONSTRUCTION
ADU specialty.
Ground-up new construction.
Same crew, same engineering rigor, same fixed-price discipline — applied to custom homes, tear-down-and-rebuild, and small multifamily under Washington's middle-housing law. Sourced permit and code citations on every page.
PROJECT_REF: 4492
Ballard Monolith
A 1,000 sqft DADU featuring vertical cedar cladding and floor-to-ceiling industrial glazing.
LocationSeattle, WA
SQ FT1000
CompletedOct 2023
The Engineering Path
Systematic construction flow
01. ANALYSIS
Site assessment, zoning review, and a written feasibility report so you know what's possible before you spend a dollar on design.
02. DESIGN
Architectural drafting and material specifications. You see real plans, real elevations, and real renderings — not back-of-napkin sketches.
03. PERMITS
Full management of city council, utility, and inspection approvals. We deal with the bureaucracy so you don't have to.
04. BUILD
Precision construction led by veteran site supervisors. Weekly progress reports, photo logs, and a single point of accountability.
05. HANDOVER
Final inspection, punch-list, warranty documentation, and key delivery. We don't disappear after the last invoice.
Plan your build
TOOLS_03 / Self-serveT_01
Cost estimator
Live build-cost range by ADU type, size, and finish tier — based on our last 24 months of completed projects.
Open tool →T_02
ROI calculator
Project monthly rental cash flow, simple payback, and 10-year property value uplift in one screen.
Open tool →T_03
Zoning snapshot
Per-city ADU rules: setbacks, parking, owner-occupancy, max sqft, and the actual permit-review window.
Open tool →PRODUCT_01
Watch us build — live build tracker preview
Open portal →Phase timeline, daily field notes, inspections, change orders, and weekly photo albums — every Golden client gets a private dashboard the day we sign.
FIELD_05 / WHY GOLDEN
Built on proof.
Not promises.
Every claim below is backed by signed contracts, public records, and documented project outcomes. We publish numbers, not adjectives.
- Building since 2012
- Delivered across Puget Sound
- Schedule adherence rate
- Structural warranty
PILLAR_02
In-house design + build
Architecture, structural engineering, MEP design, and construction under one roof. One contract, one schedule, one accountable team.
Avg. permit-to-keys: 7.4 months
PILLAR_03
Licensed, bonded, insured
Active WA general contractor license, $25K contractor bond, $2M general liability, and full workers' comp on every project — verifiable.
License GOLDESA747LZ · Active
PILLAR_04
Transparent reporting
Weekly photo logs, a live cost-and-schedule tracker, and a foreman who answers the phone. You always know what's next and what it costs.
Weekly updates · 100% of jobs
The Golden Guarantee
Your project is protected.
- ✓1-year workmanship warranty
- ✓10-year structural warranty
- ✓Lien-free completion guarantee
- ✓Daily site cleanliness standard
FIELD_06 / CLIENT FIELD REPORTS
Client reports.
From real lots.
180+ Projects · WA License GOLDESA747LZ
“Golden turned a permitting nightmare into a finished, beautiful backyard cottage. They were on schedule every single week, and the fixed-price contract held to the dollar.”
Marcus Henderson
Homeowner · Ballard, Seattle · 2023
REF_4492
“We interviewed five general contractors. Golden was the only one who walked our lot before quoting. Their structural engineer caught a foundation issue everyone else missed.”
Sade Okafor
Owner-Architect · Bellevue · 2023
REF_4376
“They converted our garage into a long-term rental that pays our mortgage. Permitted, built, and tenant-ready in 14 weeks — and the finishes look like a custom home.”
Jin & Lauren Park
Investor Homeowners · Kirkland · 2024
REF_4218
“Weekly photo updates, a real schedule we could trust, and a foreman who answered the phone on day one. After two bad GCs, that's all we wanted — and we got it.”
Ren Tanaka
Multigenerational Family · Tacoma · 2024
REF_4581
“The kitchen and primary suite addition tied into our 1962 home like it was always there. The roofline alone won us over — no awkward seam, no mismatched siding.”
Caroline Whitfield
Homeowner · Mercer Island · 2024
REF_4607
“Clean site every Friday, respectful crew, and zero change-order surprises. We'll hire Golden again the moment we're ready for the main-house remodel.”
Derek Iverson
Homeowner · Redmond · 2024
REF_4712
Material partners
SUPPLY_01 / TRUSTEDMarvin WindowsAndersenMilgardKohlerHardieTrexMitsubishi ElectricRinnaiSherwin-WilliamsSimpson Strong-Tie
Recognition
ALL PRESS →2024
REX Award — Best ADU Build
Master Builders Association of King & Snohomish Counties
2024
Houzz Best of Service
Recognized for client satisfaction across 40+ verified projects
2023
Energy Star Certified Builder
U.S. Environmental Protection Agency
Common questions
FIELD_07 / KNOWLEDGE_BASEALL FAQs →
How long does a detached ADU take from kickoff to keys?+
Plan on 8–12 months end-to-end: 6–10 weeks for design and engineering, 12–20 weeks in permit review, and 16–24 weeks of active construction. Schedules tighten when the lot is flat, the design uses a pre-approved plan, and utility upgrades are minimal.
How fast can a garage conversion (AADU) finish?+
Garage conversions and attached ADUs typically deliver in 3–5 months: 4–6 weeks of design, 8–12 weeks of permitting, and 8–14 weeks of construction. The existing slab and walls usually shave 30–40% off both the schedule and the budget compared to a new DADU.
How long is permit review in Seattle, Bellevue, Kirkland, and Tacoma?+
As of this quarter: Seattle SDCI averages 12–16 weeks, Bellevue 8–12 weeks, Kirkland 6–10 weeks, and Tacoma 8–14 weeks. Pre-approved DADU plans cut Seattle review to 4–6 weeks. We track jurisdiction velocity weekly and quote permit windows from current data, not last year's averages.
What can delay an ADU project, and how do you defend against it?+
The three usual culprits are city correction cycles, side-sewer capacity surprises, and long-lead specialty items (windows, panels, custom millwork). We mitigate by pre-checking sewer capacity at design, ordering long-lead items at permit submittal, and assigning a permit expediter to every project.
Do you build through Pacific Northwest winters?+
Yes. Foundations are sequenced for the drier shoulder seasons when possible, but framing and finish work continue year-round under temporary weather protection. Our schedules include a documented weather contingency (typically 10–15 working days) so winter rain doesn't push your handover.
From the field
ALL INSIGHTS →8 min · Sep 2025
Tacoma's ADU rules in 2026
Tacoma adopted HB 1337-compliant ADU code in 2024. Here is what the Tacoma Municipal Code now allows and where the friction still lives.
7 min · Aug 2025
Redmond ADUs and the Microsoft commute calculus
Why a Redmond DADU pencils out for tech-employee rentals — and how the city's updated code interacts with the light-rail expansion.
9 min · Jul 2025
Heat pump sizing for Puget Sound ADUs
Why oversizing kills efficiency, what the 2021 Washington Energy Code actually requires, and how we size mini-splits for a marine climate.
FAQ
Frequently asked
Who is Golden State ADU Builders?
A Washington-licensed general contractor (GOLDESA747LZ) that has built ADUs across the Puget Sound since 2012. We self-perform framing and supervision with W-2 carpenters, sub MEP to specialty-licensed crews, and operate in 32 cities from Olympia to Everett. ADUs are 80%+ of our pipeline — not a side scope.
Go deeper: Read the Puget Sound ADU timeline guide: kickoff to keys guide
What does a Puget Sound ADU cost in 2026?
All-in turn-key 2026: $330–$380/sq ft across Seattle and the Eastside, $330–$360/sq ft Tacoma/Pierce, $330–$355/sq ft Olympia. Translation: a 1,000 sq ft DADU lands $330K–$380K turn-key, a 750 sq ft DADU lands $255K–$295K. Includes design, permits, site, MEP, finishes. Excludes landscaping/PV/upgrades.
Go deeper: Read the Five hidden ADU costs that wreck Puget Sound budgets guide
How long does the full process take?
Typical clean path from first call to keys: 9–14 months. Feasibility 2 weeks + design 5–8 weeks + permit 6–18 weeks (varies by AHJ) + construction 16–28 weeks (varies by size) + closeout 2 weeks. Seattle SDCI is currently the slowest major AHJ at the permit step; Kirkland and Lacey are fastest.
Go deeper: Read the ADU rental management in the Puget Sound (2026) guide
What's the first step?
A free 30-minute consult (phone or video) where we confirm feasibility direction and review your lot using the King/Pierce/Snohomish/Thurston Assessor record. If it looks viable, the next step is a $1,500 feasibility study — a written 12–20 page report with budget, zoning analysis, and three layout options, credited back to your build contract.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
Why hire a builder who only does ADUs?
Specialization compounds. We have closed permits in every Puget Sound AHJ, our standard details for fire separation/STC 50/IECC R406 are dialed in, our crews build the same building types every month, and our warranty rate is lower because we are not relearning the building science on every project. A remodeler doing their first ADU is paying the learning curve from your budget.
Go deeper: Read the Puget Sound ADU timeline guide: kickoff to keys guide
Do you offer financing?
We do not lend, but we have relationships with the most active Puget Sound ADU lenders (BECU, Sound CU, WSECU, Washington Federal, Banner Bank, JPMorgan Chase). HomeStyle Renovation, CHOICERenovation, FHA 203(k), HELOC, and cash-out refi all work; the right choice depends on your equity, credit, and tax picture. Our financing pages walk through each by city.
What about taxes?
Property: your county will reassess your parcel under RCW 84.40.0301 after final inspection. Typical Seattle annual increase $2.8–4.2K, Bellevue $3.4–5.1K, Tacoma $1.9–2.8K. Rental income: federally taxable, depreciable 27.5-year SL (IRS Pub 527), no Washington state income tax. Tax-benefits pages model both per city.
Can I see real projects?
Yes — 140+ completed ADUs since 2017 with case studies on /projects. We host a quarterly client-consented open house and can provide 3 references in your sub-region after the second meeting. Reviews are published verified on Google, Houzz, and BBB (A+) with no compensation in exchange.
What if my city isn't listed on your site?
Call us with the address. We cover ~32 cities across King/Pierce/Snohomish/Thurston counties. If your parcel is in one of those four counties and we do not yet have a dedicated city page, we still build there — the page just has not been published yet.
What makes Golden State different from a national franchise builder?
We are locally owned (not a franchise), every PM has built ≥5 ADUs in your AHJ before yours, we publish actual cost ranges by city instead of marketing brochures, and our warranty/service is in-house — not routed through a national call center. National brands have polished marketing; we have closed permits in your reviewer's queue. Different value.
How do I know your numbers are real?
Every cost, rent, and timeline on this site is sourced — either to our own closed-contract data (sample size and date stamped), to county assessor levy schedules, or to public market data (Zillow ZORI, CoStar, RentCafe). Where we field-estimate, we label it. That is also what your lender, appraiser, and CPA need from you.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
What's the next step after the consult?
If feasibility looks viable: $1,500 feasibility study (2 weeks, fully credited back). If feasibility confirms a buildable project: design contract and selection process (~5–8 weeks). After design: permit submittal (6–18 weeks AHJ-dependent) and contract for construction. We do not pressure scheduling — most clients take 2–4 weeks between phases to make decisions.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
NEXT_STEP / FREE_CONSULTATION
Find out what your lot can build.
Leave your details. A licensed PM will call you within one business day with a realistic budget, a permit timeline for your jurisdiction, and a zoning read for your address. Free, no obligation.
- Licensed GC · Bonded · Insured
- 150+ ADUs delivered across Puget Sound
- Reply within 1 business day — usually faster
LEAD_01 / FREE_CONSULT
Start your ADU — free call
One short call. No pressure, no sales script.
INTERNAL_LINKS / Deep Map