Basement finish permits in Sammamish: fees, timeline & requirements (2026)
Everything you need to know about pulling a basement finish permit in Sammamish, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Sammamish Community Development.
Free lookup, no account needed — the office that issues the permit at your address, and a layout of the room, cited to Sammamish's source.
When does a basement finish need a permit in Sammamish?
2021 IRC R310: every sleeping room below grade requires emergency escape and rescue opening (egress window). Min sill height 44in, min net clear opening 5.7 sq ft (5.0 grade-floor), min width 20in, height 24in. Ceiling height min 7ft (R305). Entire newly conditioned area must comply with WSEC R402.
How Sammamish adopted this rule
The threshold comes from the state code (WAC 51.51), which Sammamish adopts by reference in the provision quoted below.
“The 2021 Edition of the International Residential Code, as adopted by the State Building Code Council in Chapter 51-51 WAC, as published by the International Code Council, including Appendix Q, Tiny Houses, and excluding Chapters 1, 11 and 25 through 43, is hereby adopted by the City of Sammamish”Source ↗verified 2026-10-02
Required submittals
- Floor plan w/ egress windows + ceiling heights
- Electrical layout
- Plumbing diagram
- Mechanical / HVAC plan
- WSEC compliance form (newly conditioned space)
- Smoke/CO alarm locations
Inspection sequence
- Rough-in (electrical/plumbing/mechanical)
- 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 Sammamish?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Sammamish and King County. Kolmo prepares the drawings and submittals, files the basement finish permit with Sammamish Community Development, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Sammamish basement finish quote.
Notes & caveats
Construction permit required for any habitable space addition. Smoke + CO alarms required (R314, R315). Any new circuits, plumbing fixtures, or HVAC requires trade permits.
Basement finish permit fee estimate in Sammamish
Worked example for a $40,000 basement finish project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $880.83 |
| Plan review | $572.54 |
| Technology surcharge | $218.01 |
| WA state surcharge | $6.50 |
| Estimated total | $1,677.88 |
Sammamish prices a basement finish's building permit on the value of the work: $142.05 up to $500, $236.77 for the first $2,000 plus $20.59 for each $1,000 more up to $25,000, and $710.28 for the first $25,000 plus $11.37 for each $1,000 more up to $50,000, with plan review at 65% of the permit fee. Planning's review of a remodel's building application is a $753 flat fee, and the energy code review $91. A residential combination plumbing or mechanical permit is $134 for up to 3 items and $45 for each more, and the City's electrical permit is priced on the value of the electrical work, $92.33 up to $250 and $215.45 for the first $2,000 plus $18.73 for each $1,000 more up to $25,000. The City adds a 15% technology fee to each fee (2026 Fee Schedule). Apply via mybuildingpermit.com. Computed from Sammamish'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 basement finish in Sammamish — we'll confirm which office issues the permit at that address, and you can lay out the room.
- 2. Assemble submittals: the 6 documents under Required submittals above.
- 3. Submit through the city portal: Sammamish Community Development ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (about $1,678 for a $40,000 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 Sammamish Community Development, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Basement finish permits in Sammamish — FAQ
When does a basement finish need a permit in Sammamish?
2021 IRC R310: every sleeping room below grade requires emergency escape and rescue opening (egress window). Min sill height 44in, min net clear opening 5.7 sq ft (5.0 grade-floor), min width 20in, height 24in. Ceiling height min 7ft (R305). Entire newly conditioned area must comply with WSEC R402.
How much does a basement finish permit cost in Sammamish?
For a $40,000 basement finish project, the estimated Sammamish permit fee is about $1,677.88 (building fee $880.83 + plan review $572.54 + surcharges) from Sammamish's adopted fee schedule. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.