Basement finish permits in Renton: fees, timeline & requirements (2026)
Everything you need to know about pulling a basement finish permit in Renton, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Renton Community and Economic Development — Development Services.
Free lookup, no account needed — your lot polygon, zoning, setbacks and overlays, cited to Renton's source.
When does a basement finish need a permit in Renton?
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 Renton adopted this rule
The threshold comes from the state code (WAC 51.51), which Renton adopts by reference in the provision quoted below.
“4-5-055 INTERNATIONAL RESIDENTIAL CODE ADOPTED: The 2021 Edition of the International Residential Code (IRC), as adopted and amended by the State Building Code Council in chapter 51-51 WAC, as published by the International Code Council, is adopted by reference, with the City’s amendments thereto, as specified in subsections A and B of this Section. Chapter 1, Scope and Administration, is not adopted and the Construction Administrative Code, as set forth in RMC 4-5-060 , shall be used in place of IRC Chapter 1, Scope and Administration;”Source ↗verified 2026-05-17
Required submittals
- Application Form, Building Division (RMC 4-8-120B col "Single Family/Multi-Family Interior Remodel")
- Architectural Plans, Detached and 2 Attached Dwellings — when applicable
- Floor plan showing existing + proposed work (RMC 4-8-120B implied)
- Energy Code Checklist, Residential — required when newly conditioned space (basement finish, garage conversion) or envelope changes
- Structural Plans + Calcs — when structural changes (header, beam, lateral) are proposed
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 Renton?
Kolmo Construction is a licensed Washington general contractor — KOLMOL*753JS, active through April 10, 2027, bonded and insured — working throughout Renton and King County. Kolmo prepares the drawings and submittals, files the basement finish permit with Renton Community and Economic Development — Development Services, carries the project through review and inspections, and performs the construction. Call (206) 410-5100 for a Renton basement finish quote.
Notes & caveats
Basement finish — Interior Remodel submittals per RMC 4-8-120B. Newly conditioned area triggers WSEC R-prescriptive checklist + egress windows (IRC R310) per Renton building handout.
Basement finish permit fee estimate in Renton
Worked example for a $40,000 basement finish project (building permit). Your actual fee scales with project valuation.
| Building permit fee | $896.72 |
| Plan review | $582.87 |
| Technology surcharge | $73.98 |
| WA state surcharge | $6.50 |
| Estimated total | $1,560.07 |
Renton prices a basement finish's building permit on the value of the work: $44 up to $500, $119.66 for the first $2,000 plus $22.99 for each $1,000 more up to $25,000, and $648.47 for the first $25,000 plus $16.55 for each $1,000 more up to $50,000. Plan check is 65% of the permit fee, three review cycles included, and the $6.50 state building code fee applies. A residential plumbing permit is a $69 base fee plus $12 a fixture, a mechanical permit $69 plus $28 for each appliance, fan or gas piping system, and the City's electrical permit for new circuits without a service change $222 at the least; plan review on those permits, where required, is 40% of the permit fee. The City adds its 5% technology surcharge to each of these fees (Fee Schedule 2025-2026). Apply via permitting.rentonwa.gov. Computed from Renton'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 Renton basement finish — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
- 2. Assemble submittals (5).
- 3. Submit through the city portal: Renton Community and Economic Development — Development Services ↗
- 4. Track review. Respond to reviewer comments promptly.
- 5. Pay issuance fees (about $1,560 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 Renton Community and Economic Development — Development Services, handles reviewer comments, and builds the project.
Licensed WA general contractor KOLMOL*753JS · bonded & insured
Basement finish permits in Renton — FAQ
When does a basement finish need a permit in Renton?
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 Renton?
For a $40,000 basement finish project, the estimated Renton permit fee is about $1,560.07 (building fee $896.72 + plan review $582.87 + surcharges) from Renton's adopted fee schedule. Land use, fire and engineering review, intake, impact and utility fees, where they apply, are charged separately.