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Construction Permit - Addition or Alteration in Seattle, Washington

Required to add to or alter an existing building in Seattle. Listed by SDCI under Permits We Issue (A-Z) as "Construction Permit - Addition or Alteration".

Reviewed 2026-09-15 · Source

When you need this permit

  • A construction permit is required before beginning an addition or alteration
  • Work is reviewed against the 2021 Seattle Building Code or the 2021 Seattle Residential Code depending on the structure
  • Energy-code compliance is reviewed under the 2021 Seattle Energy Code

Required documents

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Fee schedule

Building permit fee
Seattle sets most development fees from a Development Fee Index calculated from the project's valuation, under Table D-1 for 22.900D.010 of the 2026 Fee Subtitle (Seattle Municipal Code Chapter… Show full citationSeattle sets most development fees from a Development Fee Index calculated from the project's valuation, under Table D-1 for 22.900D.010 of the 2026 Fee Subtitle (Seattle Municipal Code Chapter 22.900, effective January 1, 2026). The Subtitle states the development fee "The development fee shall consist of a permit fee and, where plans are reviewed, a separate plan review fee. The permit fee and plan review fee shall be determined based on valuation". The index begins at "$325 for the first $1,000 of value or fraction thereof", then "$325 for the first $1,000 of value plus $1.60 for each additional $100 of value or fraction thereof". A technology fee is added on top "in the amount of five percent of all fees or charges required under the above chapters". Hourly work is billed at the SDCI hourly rate: "The hourly rate for land use review is $551. The rate for all other hourly fees is $292 an hour". Figures are quoted from the 2026 Fee Subtitle as published by SDCI and are not a quote for your project; valuation drives the number and SDCI determines valuation. For a building permit with or without mechanical, Table D-2 for 22.900D.010 sets both the permit fee and the plan review fee at 100% of the Development Fee Index.
From the city's own schedule - see notes

Review timeline

Plan review
Not published — contact the department

How long did your Construction Permit - Addition or Alteration permit actually take in Seattle?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

    Tips

    • Seattle amends the International codes into its own Seattle Building, Residential and Energy Codes - the governing text is the Seattle edition, not the International one
    • The technology fee applies on top of the listed fee, not inside it
    • Field inspections as required by SDCI for the approved scope

    Frequently asked questions

    Seattle requires a construction permit - addition or alteration for: A construction permit is required before beginning an addition or alteration; Work is reviewed against the 2021 Seattle Building Code or the 2021 Seattle Residential Code depending on the structure; Energy-code compliance is reviewed under the 2021 Seattle Energy Code. If your project isn't listed, confirm with Seattle Department of Construction & Inspections (SDCI) at (206) 684-8600 before starting work.

    In Seattle, the published Building permit fee is: From the city's own schedule - see notes. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

    Seattle does not publish a plan-review timeline for this permit. Contact Seattle Department of Construction & Inspections (SDCI) at (206) 684-8600 for current turnaround.

    You'll need: Site plan; Floor plans; Elevations and sections sufficient to show code compliance. See the required-documents checklist on this page for details on each.

    Apply through Seattle Department of Construction & Inspections (SDCI) at 700 5th Ave, Suite 2000, Seattle, WA, 98104. Phone: (206) 684-8600. Office hours: Mailing address: P.O. Box 34019, Seattle, WA, 98124-4019. Violation Complaint Line: (206) 615-0808. Counter hours are not published on the department pages read for this entry - confirm before travelling.. Official information: https://www.seattle.gov/construction-and-inspections.

    No. SDCI publishes a 2021 Seattle Building Code which contains substantial copyrighted material from the 2021 International Building Code but is Seattle's own adopted edition.

    Sources & verification

    Key facts verified against official sources. Last reviewed 2026-09-15.

    Fee schedules

    Department & other records

    Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Seattle building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

    Property Access

    Seattle's permit history is searchable by address

    192,660 permits in our copy of Seattle's register — searchable by street address, with permit type, status, issued date and valuation where the city publishes them. This is what we hold, not a statement of everything Seattle has issued.

    140,002 of these 192,660 permits — 72.7% — carry an issued date, and those run from 1986 to 2026. The remaining 52,658 have no date at all.

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    Other permits in Seattle

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