Addition permits in Woodinville: fees, timeline & requirements (2026)
Everything you need to know about pulling a home addition permit in Woodinville, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Woodinville Development Services.
Free lookup, no account needed — your lot polygon, zoning, setbacks and overlays, cited to Woodinville's source.
When does a home addition need a permit in Woodinville?
An addition enlarges the house and needs a building permit in Woodinville: the City adopts the 2021 IRC with its permit chapter (WMC 21.62.010), and its list of work exempt from a building permit (WMC 21.62.070) names no addition. The City issues one Combined Building Permit that covers the addition's mechanical and plumbing work. Electrical work needs a permit from L&I: the City issues no electrical permits and does no electrical inspections. The addition must meet the zone's setbacks, height and lot coverage. For the fee, Woodinville values an addition by its floor area at the rates in Table 21.62.060, not by the contract price (WMC 21.62.060(1)). Woodinville must decide a building permit within 120 days of a complete application, not counting the time it waits on the applicant (WMC 21.80.210(3)).
From Woodinville's own code
“2021 Edition of the International Residential Code, Chapter 51-51 WAC”Source ↗verified 2026-11-07
Required submittals
- Site plan with north arrow, property lines, setbacks, existing + proposed structures, lot coverage calculation
- Floor plan existing and proposed (dimensioned, 1/4" = 1' min)
- Elevations all affected sides (existing + proposed, height-to-grade)
- Foundation plan + footing details (if footprint addition)
- Framing plan (floor + roof + lateral)
- Wall section with insulation values per WSEC
- Structural calculations (when ≥500 sqft addition or out of IRC prescriptive envelope)
- WSEC compliance form (Energy Code Compliance Certificate)
- Manual J HVAC sizing calculation for new conditioned area
- Window/door schedule with NFRC U-factor and SHGC values
- Soils report if footing on slope or expansive soils
Inspection sequence
- Foundation/footing
- Plumbing rough-in
- Electrical rough-in
- Mechanical rough-in
- Framing
- Insulation
- Drywall
- Final
Contractor specialties needed
General contractor · Electrician (journey-level 01 or residential 02) · Plumber · Mechanical contractor
Who can do this work in Woodinville?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Woodinville and King County. Kolmo prepares the drawings and submittals, files the home addition permit with Woodinville Development Services, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Woodinville home addition quote.
Notes & caveats
2021 IRC R301 governs framing. WSEC R402.1 sets envelope requirements. New conditioned space requires Manual J HVAC sizing. Lateral load path continuity required for vertical additions. Most WA cities use a uniform fee bracket (UBC Table 1-A) for the building permit; plan review fee is typically 65% of building permit fee.
Addition permit fee estimate in Woodinville
Worked example for a 400 sq ft addition (building permit), valued at $66,268: Woodinville values it at $165.67 a square foot (WMC Table 21.62.060), not at its contract price. Your actual fee scales with the floor area.
| Building permit fee | $1,114 |
| Plan review | $724.10 |
| WA state surcharge | $6.50 |
| Estimated total | $1,844.60 |
Plan-review fee scales with valuation per UBC Table 1-A. State surcharge $6.50 per building permit. Trade permits (E/P/M) separate. Apply through Woodinville's online Permit Portal (aca-prod.accela.com/woodinville/default.aspx); the Apply for a Permit Online page (woodinville.gov/347/Apply-for-a-Permit-Online) explains the account setup. Computed from Woodinville's adopted fee schedule · source ↗. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.
How to apply yourself
- 1. Confirm your parcel's zoning & overlays. Run an address lookup for your Woodinville home addition — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
- 2. Assemble submittals (11).
- 3. Submit through the city portal: Woodinville Development Services ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (about $1,845 for a 400 sq ft addition) and pick up the permit. Inspection card travels with the job.
Or have Kolmo do it
Kolmo prepares the drawings and submittals, files with Woodinville Development Services, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Addition permits in Woodinville — FAQ
When does a home addition need a permit in Woodinville?
An addition enlarges the house and needs a building permit in Woodinville: the City adopts the 2021 IRC with its permit chapter (WMC 21.62.010), and its list of work exempt from a building permit (WMC 21.62.070) names no addition. The City issues one Combined Building Permit that covers the addition's mechanical and plumbing work. Electrical work needs a permit from L&I: the City issues no electrical permits and does no electrical inspections. The addition must meet the zone's setbacks, height and lot coverage. For the fee, Woodinville values an addition by its floor area at the rates in Table 21.62.060, not by the contract price (WMC 21.62.060(1)). Woodinville must decide a building permit within 120 days of a complete application, not counting the time it waits on the applicant (WMC 21.80.210(3)).
How much does a home addition permit cost in Woodinville?
Woodinville values an addition by its floor area, not its contract price: a 400 sq ft addition at $165.67 a square foot (WMC Table 21.62.060) is valued at $66,268, and its estimated Woodinville permit fee is about $1,844.60 (building fee $1,114 + plan review $724.10 + surcharges) from Woodinville's adopted fee schedule. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.