Seattle, WA · Additions
MODERN ADDITIONS Builder in Seattle, WA
Additions are where most contractors get into trouble — roof tie-ins, foundation underpinning, and continuity of the weather envelope are unforgiving details. We treat additions like new construction grafted onto an existing home, with engineered connections and fully blended exteriors.
Build timeline
Project dependent
Typical sqft
Custom
Seattle cost
$220K – $750K
Permit window
12–16 wk
What modern additions looks like in Seattle
MODERN ADDITIONS projects in Seattle are shaped by local zoning (SF 5000 / NR2 / NR3), a lot minimum of 3,200 sqft, and the kinds of sites we see day-to-day: Ballard, Queen Anne, Capitol Hill. Below is what every Seattle Additions project from Golden State includes — fixed-price, one contract, one warranty.
- ✓Structural + foundation engineering
- ✓Roof + envelope tie-in detailing
- ✓Underpinning where required
- ✓Selective demolition + protection
- ✓New space framing, MEP, finish
- ✓Whole-home punch list
Other services in Seattle
More from Golden State ADU in Seattle
DADU
DETACHED ADU in Seattle
Stand-alone backyard cottages built from the ground up — engineered for rental income, multi-generational living, or your home office.
AADU
ATTACHED ADU in Seattle
Seamlessly integrated additions — basement, ground-floor, or wing conversions that maintain the architectural integrity of your existing home.
Garage
GARAGE CONV. in Seattle
Convert an under-used garage into a high-end studio, office, or rental quarter without surrendering your driveway.
GC
GENERAL CONTRACTING in Seattle
Full-service general contracting for remodels, renovations, and ground-up custom homes throughout the Puget Sound region.
Feasibility
FEASIBILITY STUDIES in Seattle
Before you commit, we analyze zoning, lot coverage, setbacks, utilities, and ROI so you have a real number — not a guess.
MODERN ADDITIONS across the Puget Sound
MODERN ADDITIONS builders in nearby cities
Start your Seattle Additions feasibility
$1,500 buys lot analysis, Seattle zoning verification, and a fixed price you can build a budget on.
Request Seattle feasibilityFrequently asked
What is included in MODERN ADDITIONS in Seattle?
Our MODERN ADDITIONS in Seattle scope includes design through completion: feasibility, schematic design, construction documents, permit submittal and review management, construction with one self-performed framing crew plus L&I-licensed MEP subcontractors, all required WA inspections, certificate of occupancy, and warranty. One contract, one license number, one warranty — not a coordination headache across five vendors.
How is MODERN ADDITIONS in Seattle different from a generic remodel?
MODERN ADDITIONS in Seattle carries code, permit, and construction details that a one-off remodeler hasn't repeated enough times to optimize. Examples: IECC R406 envelope path selection, fire separation when units are within 5 ft, side-sewer slope requirements, IRC Appendix AQ when permitted as a tiny house, separate utility metering rules. We do this scope every month — repetition is what makes our first-cycle approval rate and our schedule reliability stand out.
What is the typical price range for MODERN ADDITIONS in Seattle?
MODERN ADDITIONS in Seattle pricing in 2026 lands in the $295–$465/sqft all-in range depending on size, lot conditions, finish tier, and AHJ. The wide range is real — small lots with difficult access, soils requiring pier-and-beam, or service upgrades push the upper end; flat lots with good access and a catalog plan land at the lower end. Our feasibility report gives you a ±15% number tailored to your specific lot in two weeks.