Can I tour a project like "Bellevue Wing"?

Yes — we typically have 6–10 ADUs in framing or finish at any time across the Puget Sound, so we can usually arrange a site walk on a project at the same stage you're planning. For completed projects, tours depend on the current owner's availability and privacy preferences. Request a tour and we'll match you to the closest active or completed project that resembles "Bellevue Wing" in size, configuration, and AHJ. Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide (/guides/eastside-deck-cost-permits).

What did this project actually cost?

Each project page includes the all-in cost range for the size and configuration shown, scaled to 2026 prices. Actual contract value at time of build is confidential to the client, but the range we publish is anchored in real numbers from our bid archive — not aspirational pricing. For a tailored estimate against your lot, run our feasibility study or use the cost calculator. Go deeper: Read the Five hidden ADU costs that wreck Puget Sound budgets guide (/guides/hidden-adu-costs).

How long did this project take?

Most projects of this size and configuration run 9–14 months from contract to certificate of occupancy: 6–8 weeks of design, 8–16 weeks of permit, 18–26 weeks of construction. Schedule variance is driven by AHJ workload, owner selection pace, and field-discovered conditions during demo or excavation. We publish a Gantt at contract and update it weekly. Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide (/guides/eastside-deck-cost-permits).

Could you build "Bellevue Wing" again on my lot?

Often yes — most of our projects are anchored on repeatable design DNA (envelope details, structural assemblies, MEP standard layouts) that adapt to different lot conditions with modest configuration changes. We'll review your lot's zoning, soils, and access to confirm fit. Where the original layout doesn't fit, we propose the closest workable adaptation that preserves the look you liked. Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide (/guides/eastside-deck-cost-permits).

What inspections did "Bellevue Wing" go through?

Standard Puget Sound ADU inspection sequence applied: footing, underfloor MEP, framing, plumbing rough, electrical rough, mechanical rough, insulation, drywall nailing, shower pan, gas piping, final building, final plumbing, final electrical, final mechanical, and final energy verification (blower-door ≤3 ACH50). All passed with no notable callbacks — typical for our builds because we run internal QA checklists at each milestone. Go deeper: Bellevue ADU permit timeline (/permits/bellevue).

REF_4376 · Attached ADU · Bellevue, WA

Bellevue Wing

A 720 sqft side-yard AADU grafted onto a 1962 craftsman in West Bellevue — independent entry, separate utilities, no shared interior wall openings.

Type: Attached ADU
Sqft: 720
Beds / Baths: 1 / 1
Completed: Aug 2023
Duration: 28 wks
Budget: $258,000

Bellevue Wing — Attached ADU in Bellevue, WA

01 / BRIEF

What the owner asked for

A multi-generational family wanted a fully independent unit for an aging parent without the privacy compromises of a basement conversion. Bellevue Land Use Code 20.30.130 was rewritten in 2023 to allow AADUs by-right with a separate front door, so we proposed a single-story east-side addition that ties into the existing roofline at the gable.

02 / CHALLENGE

What stood in the way

The existing 100A service was already at 86% of nameplate during the December peak — a load calc per NEC 220.83 showed no headroom for an electric range, heat pump, and EV charger. Bellevue also requires 20-foot side-yard separation from the neighbor's eave for any habitable window.

03 / APPROACH

How we solved it

We upgraded the main panel to 200A and ran a sub-fed 100A panel into the AADU on a separate meter base (PSE Service Order #SO-22-44109). All east-facing AADU windows were placed in the corridor wall and clerestoried above 6'-8" to avoid line-of-sight to the neighbor. A 24" cricket on the existing roof shed water away from the new flat-roof transition.

04 / OUTCOME

What got delivered

Built in 19 weeks of construction after a 9-week Bellevue permit review. The parent moved in three weeks before Thanksgiving 2023. Property reassessment came in $187K above the build cost, and the family refinanced the entire mortgage at the same rate held since 2021.

SPEC_05 / FACTS

Project specification

Footprint: 720 sqft single-story
Bedrooms / baths: 1 / 1
Ceiling height: 9'-0"
Energy code path: Prescriptive (R-21 / R-49)
Side-yard setback: 10'-0" (code minimum 5')
Parking: 1 existing on-site

SCHEDULE_06 / PHASES

28-week delivery

01
Feasibility & design
4–6 wks
Site survey, zoning memo, schematic plans, owner review.
02
Construction docs
3–4 wks
Structural, MEP, energy compliance, permit-ready set.
03
Permit review
9 wks
City corrections, utility sign-offs, building permit issued.
04
Site work + foundation
3–4 wks
Erosion control, excavation, footings, slab or stem wall.
05
Framing + dry-in
5–6 wks
Floor, walls, roof, windows, weather-resistive barrier.
06
MEP rough-in + insulation
4–5 wks
Plumbing, electrical, HVAC, blower-door prep.
07
Finish + cabinetry
6–8 wks
Drywall, paint, flooring, cabinets, tile, fixtures.
08
Inspections + handover
1–2 wks
Final inspections, punch-list, 19-week build closeout.

MATERIAL_07

Materials

Cladding
Hardie Artisan V-rustic, 7" exposure, ben-moore Kendall Charcoal
Roofing
CertainTeed Landmark Pro, Charcoal Black
Windows
Milgard Tuscany V400, vinyl, U-0.30
Entry door
Therma-Tru S3550 fiberglass, full-lite frosted

SYSTEM_08

Systems

Heating / cooling
Daikin RXL15QMVJU 15K BTU single-zone
Water heating
Rinnai RU199iN gas tankless (shared with main)
Electrical
200A main + 100A AADU sub-panel, separate meter

PERMIT_09 / RECORD

Permits & compliance

Permit number
Bellevue BLD-22-00731-RNCR
Utility coordination
PSE SO-22-44109 (electrical), Bellevue Utilities #BU-22-1198
Land-use review
Administrative AADU permit (no DR required)

METRIC_10 / OUTCOME

By the numbers

$8,440
Final permit fee: +$187,000
Reassessment delta: 2.6
Blower door (ACH50): 0
Days over schedule

LESSON_11 / FIELD NOTES

What we'd repeat

Pulling the load calc before schematic design pre-empted a 4-week panel-upgrade scramble at rough-in.
Bellevue's 2023 AADU code allows interior connecting doors between primary and AADU as long as they're not the only AADU egress — useful for aging-in-place layouts.

Code · permits · cost

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(425) 642-4142

ARCHIVE_∞ / MORE

Other field reports

FAQ

Frequently asked

Can I tour a project like "Bellevue Wing"?
Yes — we typically have 6–10 ADUs in framing or finish at any time across the Puget Sound, so we can usually arrange a site walk on a project at the same stage you're planning. For completed projects, tours depend on the current owner's availability and privacy preferences. Request a tour and we'll match you to the closest active or completed project that resembles "Bellevue Wing" in size, configuration, and AHJ.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
What did this project actually cost?
Each project page includes the all-in cost range for the size and configuration shown, scaled to 2026 prices. Actual contract value at time of build is confidential to the client, but the range we publish is anchored in real numbers from our bid archive — not aspirational pricing. For a tailored estimate against your lot, run our feasibility study or use the cost calculator.
Go deeper: Read the Five hidden ADU costs that wreck Puget Sound budgets guide
How long did this project take?
Most projects of this size and configuration run 9–14 months from contract to certificate of occupancy: 6–8 weeks of design, 8–16 weeks of permit, 18–26 weeks of construction. Schedule variance is driven by AHJ workload, owner selection pace, and field-discovered conditions during demo or excavation. We publish a Gantt at contract and update it weekly.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
Could you build "Bellevue Wing" again on my lot?
Often yes — most of our projects are anchored on repeatable design DNA (envelope details, structural assemblies, MEP standard layouts) that adapt to different lot conditions with modest configuration changes. We'll review your lot's zoning, soils, and access to confirm fit. Where the original layout doesn't fit, we propose the closest workable adaptation that preserves the look you liked.
Go deeper: Read the Eastside deck cost & permits: cedar, IPE, composite (2026) guide
What inspections did "Bellevue Wing" go through?
Standard Puget Sound ADU inspection sequence applied: footing, underfloor MEP, framing, plumbing rough, electrical rough, mechanical rough, insulation, drywall nailing, shower pan, gas piping, final building, final plumbing, final electrical, final mechanical, and final energy verification (blower-door ≤3 ACH50). All passed with no notable callbacks — typical for our builds because we run internal QA checklists at each milestone.
Go deeper: Bellevue ADU permit timeline

INTERNAL_LINKS / Deep Map