Window replacement permits in Mercer Island: fees, timeline & requirements (2026)
Everything you need to know about pulling a window replacement permit in Mercer Island, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Mercer Island Community Planning & Development.
Free lookup, no account needed — the office that issues the permit at your address, cited to Mercer Island's source.
When does a window replacement need a permit in Mercer Island?
Exempt: in-kind window replacement for IRC structures where no alteration of structural members is required, safety glazing is provided where required, and window fall protection is provided where required. Permit required for: new openings, larger openings, or any structural alteration.
How Mercer Island adopted this rule
The threshold comes from the state code (WAC 51.51), which Mercer Island adopts by reference in the provision quoted below.
“The 2021 Edition of the International Building Code (IBC), including the adoption of ICC/ANSI A117.1-2017, Requirements for Accessible and Useable Buildings and Facilities, as adopted and amended by the State Building Code Council in WAC Chapter 51-50, as published by the International Code Council, excluding Chapter 1, Administration, is adopted by reference, together with the following amendments and additions. The Construction Administrative Code, as set forth in chapter 17.14 MICC, shall be used in place of IBC Chapter 1, Administration.”Source ↗verified 2026-04-29
Required submittals
- If new/enlarged opening: header schedule, structural detail, WSEC NFRC sticker for U-factor
Inspection sequence
- Rough-opening inspection (if structural)
- Final
Contractor specialties needed
General contractor
Who can do this work in Mercer Island?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Mercer Island and King County. Kolmo prepares the drawings and submittals, files the window replacement permit with Mercer Island Community Planning & Development, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Mercer Island window replacement quote.
Notes & caveats
Per multi-jurisdiction tip sheet (Mercer Island column): exterior doors/windows/skylights "that require a new opening or larger opening" require a permit. From MICC 17.14.010 §105.2 (enumerated exceptions): "In-kind window replacement for IRC structures where no alteration of structural members is required, safety glazing is provided where required, window fall protection is provided where required..." Window awnings supported by an exterior wall not projecting more than 54 inches and not requiring additional support are also exempt.
Window replacement permit fee estimate in Mercer Island
Worked example for an $8,000 window replacement project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $258.27 |
| Plan review | $180.79 |
| WA state surcharge | $6.50 |
| Estimated total | $445.56 |
Where window work needs a permit on Mercer Island, such as a new or larger opening, the building permit is priced on the value of the work: $40.06 up to $500, and $118.83 for the first $2,000 plus $23.24 for each $1,000 more up to $25,000; plan check adds 70% of that fee where plans are reviewed (2026 Fee Schedule). Computed from Mercer Island'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. Check who issues the permit. Run an address lookup for your window replacement in Mercer Island — we'll confirm which office issues the permit at that address.
- 2. Assemble submittals: what Required submittals above lists.
- 3. Submit through the city portal: Mercer Island Community Planning & Development ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (about $446 for an $8,000 project) and pick up the permit. Inspection card travels with the job.
Or have Kolmo do it
Kolmo prepares the drawings and submittals, files with Mercer Island Community Planning & Development, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Window replacement permits in Mercer Island — FAQ
When does a window replacement need a permit in Mercer Island?
Exempt: in-kind window replacement for IRC structures where no alteration of structural members is required, safety glazing is provided where required, and window fall protection is provided where required. Permit required for: new openings, larger openings, or any structural alteration.
How much does a window replacement permit cost in Mercer Island?
For a $8,000 window replacement project, the estimated Mercer Island permit fee is about $445.56 (building fee $258.27 + plan review $180.79 + surcharges) from Mercer Island's adopted fee schedule. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.