Federal Way, WA · Additions
MODERN ADDITIONS Builder in Federal Way, 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
Federal Way cost
$194K – $660K
Permit window
10–14 wk
What modern additions looks like in Federal Way
MODERN ADDITIONS projects in Federal Way are shaped by local zoning (RS-7.2 / RS-9.6 / RS-15.0), a lot minimum of 7,200 sqft, and the kinds of sites we see day-to-day: West Campus, Twin Lakes, Mirror Lake. Below is what every Federal Way 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 Federal Way
More from Golden State ADU in Federal Way
DADU
DETACHED ADU in Federal Way
Stand-alone backyard cottages built from the ground up — engineered for rental income, multi-generational living, or your home office.
AADU
ATTACHED ADU in Federal Way
Seamlessly integrated additions — basement, ground-floor, or wing conversions that maintain the architectural integrity of your existing home.
Garage
GARAGE CONV. in Federal Way
Convert an under-used garage into a high-end studio, office, or rental quarter without surrendering your driveway.
GC
GENERAL CONTRACTING in Federal Way
Full-service general contracting for remodels, renovations, and ground-up custom homes throughout the Puget Sound region.
Feasibility
FEASIBILITY STUDIES in Federal Way
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 Federal Way Additions feasibility
$1,500 buys lot analysis, Federal Way zoning verification, and a fixed price you can build a budget on.
Request Federal Way feasibilityFrequently asked
What is included in MODERN ADDITIONS in Federal Way?
Our MODERN ADDITIONS in Federal Way 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 Federal Way different from a generic remodel?
MODERN ADDITIONS in Federal Way 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 Federal Way?
MODERN ADDITIONS in Federal Way 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.