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BUDGET_08 / TURN-KEY RANGES

Real numbers.
Fixed-price contracts.

We don't quote per-square-foot averages and revise mid-project. You get a fixed-price contract before we break ground — and these tiers are how we get there.

TIER_01

ESSENTIALS

$325 – $385K
400–600 sqft DADU

Code-compliant turn-key DADU with smart, durable finishes. Built for rental income or guest space.

  • +Standing-seam metal roof
  • +Hardie + cedar accent siding
  • +Quartz counters, IKEA-grade cabinets
  • +Mini-split HVAC
  • +Standard appliance package
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TIER_02Most chosen

SIGNATURE

$385 – $475K
600–850 sqft DADU

Our most popular tier. Architect-led design, custom millwork, and full Pacific Northwest material palette.

  • +Full architect design package
  • +Vertical cedar siding
  • +Marvin or Andersen 100 windows
  • +Custom kitchen + closet millwork
  • +Engineered hardwood throughout
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TIER_03

BESPOKE

$475 – $750K+
850–1,200+ sqft DADU

Custom architecture, premium materials, structural glass, and integrated landscape design. Our flagship work.

  • +Bespoke architectural design
  • +Steel + glass structural glazing
  • +Stone or concrete countertops
  • +Smart-home integration
  • +Hardscape + landscape design
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Estimator

CALC_01 / RANGES
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Project type
Square footage700
4001200
Finish tier
ESTIMATE_OUT
Turn-key range
$266K – $364K
≈ $450 / sqft midpoint

Estimates use 2025 Puget Sound averages from our last 24 months of completed builds. Final fixed-price proposal requires a feasibility study of your lot.

COMMON QUESTIONS / COST
What does a detached ADU actually cost in 2026?
Most of our turn-key DADUs land between $325,000 and $525,000, or roughly $400–$525 per square foot all-in (design, permits, site work, build, and warranty). The spread is driven by size, finish tier, and how much the lot fights you — slope, trees, and utility distance are the big movers.
What does an attached ADU (AADU) or basement conversion cost?
AADUs and basement conversions typically run $185,000–$310,000. They benefit from shared walls, existing utilities, and a smaller permit scope, but ceiling height, egress windows, and separate-entry framing can quietly add $20K–$40K if the existing house wasn't designed for it.
What does a garage conversion cost?
Garage conversions usually fall between $145,000 and $235,000 depending on whether the slab needs to come up, the roof needs structural reinforcement, and how far the kitchen/bath plumbing runs to the existing main line. The single biggest variable is insulation upgrades — most older garages need full envelope work to meet code.
What's the price per square foot — and why is that number misleading?
Our DADUs pencil to roughly $400–$525/sqft, AADUs $325–$425/sqft, and garage conversions $300–$425/sqft. The number is useful for sanity checks, but smaller ADUs always cost more per sqft because kitchens, baths, and utility hookups don't scale down. Compare total project cost against scope, not /sqft against /sqft.
What hidden costs blow up an ADU budget?
The five we see most: side-sewer upgrades ($8K–$25K), electrical service panel upsize ($4K–$12K), tree-protection or removal permits ($2K–$15K), stormwater retention ($5K–$20K), and arborist or geotech reports ($2K–$6K). Every Golden proposal includes a site-conditions allowance so these show up as line items, not surprise change orders.
Do you bid fixed-price or time-and-materials?
Every contract is a fixed-price agreement signed after design and engineering are complete. We don't bid T&M for ADUs because the scope is knowable — anyone who insists on T&M is asking you to absorb their risk. The only variable line items are owner-selected allowances (appliances, plumbing fixtures, flooring) that you control.
How accurate is your free consultation budget range?
Our consult-stage range is typically ±15% of the eventual fixed-price contract. We tighten that to ±3% during schematic design after the survey and geotech are in. If a competitor is offering ±0% before you've paid for engineering, they're either padding the number or about to write change orders.