The permit process is one of the most common sources of anxiety for Seattle homeowners planning a deck. Questions we hear constantly: Do I even need one? How long does it take? What if I just skip it? This guide answers all of them — based on the actual permit process we navigate for clients across King County and the City of Seattle every year.
Do You Need a Permit?
In most cases, yes. In King County and the City of Seattle, a building permit is required for any deck that is either attached to the house or elevated more than 30 inches above grade at any point. This covers the vast majority of residential deck projects.
Freestanding, ground-level structures under 200 square feet and under 30 inches in height may be exempt — but the rules depend on your specific jurisdiction and zoning designation. When in doubt, ask before building. The penalty for constructing without a required permit is far worse than the cost and time of getting one.
One thing to understand clearly: skipping the permit doesn't make the deck illegal only if someone notices. An unpermitted structure is legally unpermitted regardless of whether a code enforcement officer ever drives past your house. This has real consequences when you sell your home, and in some cases before that.
King County vs. City of Seattle — Which Jurisdiction Applies?
This is a significant source of confusion for homeowners. The City of Seattle has its own permitting authority — the Seattle Department of Construction and Inspections (SDCI) — and operates completely independently from King County. If your property is within Seattle city limits, you go through SDCI. If your property is in unincorporated King County or one of the incorporated cities in the county, you go through a different office.
Most smaller cities in King County — Bellevue, Kirkland, Redmond, Renton, Bothell, Sammamish, and others — have their own permitting offices and process permits under their local codes, which are based on but not identical to King County's. The requirements are similar, but the specific online portal, fee schedule, and contact office differ.
We work across all of these jurisdictions regularly and know the requirements, timelines, and common correction requests for each. One of the first things we do for a new client is confirm the exact jurisdiction and pull the current requirements from that office before any design work begins.
The Step-by-Step Permit Process
Here is what the permit process looks like for a standard residential deck in King County or the City of Seattle.
The first step is preparing structural drawings. For most elevated decks, King County and SDCI require construction drawings showing plan view and elevation, footing specifications, beam and joist sizing, and connection details at the ledger and post bases. These don't require a licensed architect in most cases, but they need to be complete, accurate, and drawn to scale. We work with experienced draftspersons who produce King County-compliant drawings efficiently, and we engage structural engineers for complex or hillside projects.
The second step is submitting the application. Both King County and SDCI accept applications through online permitting portals. The application includes the drawings, a project description, site address, contractor license information, and the permit fee. The fee is calculated based on the declared project value.
The third step is plan review. This is where the timeline uncertainty lives. Standard plan review in King County typically takes three to eight weeks depending on department workload and time of year. Spring and summer are the busiest review periods. Both King County and SDCI offer expedited review for an additional fee — typically 50 to 100 percent of the standard permit fee — which can reduce review time to one to two weeks. For projects with tight timelines, expedited review is often worth the cost.
The fourth step is permit issuance. Once plan review is complete and any required corrections are addressed and resubmitted, the permit is issued. The permit document is posted at the job site during construction.
The fifth step is construction with required inspections. King County and SDCI require inspections at two critical points during construction. The footing inspection happens before concrete is poured for the post footings — the inspector needs to see the hole dimensions and any required rebar before concrete is placed. The framing inspection happens after structural framing is complete but before surface decking is installed — the inspector verifies beam sizing, joist spacing, ledger connection, and hardware. These inspections are not optional, and construction cannot proceed past each inspection point without approval.
The sixth step is the final inspection. After construction is complete, a final inspection confirms the deck was built per the approved drawings and all code requirements are met. The permit is then closed and recorded with the county or city as part of the property record.
How Much Does a Deck Permit Cost in King County?
The permit fee for a residential deck in King County typically runs $300–$800, calculated as a percentage of the declared project value. A $25,000 deck project in unincorporated King County generates a permit fee roughly in the $400–$600 range. Fee schedules in the City of Seattle and individual cities like Bellevue or Kirkland follow their own formulas but are generally in a similar range.
If structural drawings are needed — required for most elevated decks — add $500–$1,500 for drafting. If you opt for expedited plan review, add the expedited fee on top of the base permit fee.
We include permit management as part of every project at no separate charge. We prepare or coordinate the required drawings, submit the application, respond to plan review correction letters, schedule and coordinate required inspections, and manage the permit close-out after the final inspection. You don't need to navigate the permit portal or speak with the building department yourself.
Common Reasons Permits Get Rejected or Delayed
Plan review corrections are common and don't necessarily mean a project has a fundamental problem — but they add time. Resubmittal and second review takes additional weeks.
The most common issues we see on correction letters are undersized footings — where the footing diameter or depth doesn't meet the code requirement for the tributary load — setback violations where the proposed deck encroaches on the required setback from property lines or recorded easements, incomplete drawings that are missing required dimensions or connection details, and ledger attachment details that don't meet the current code requirements for weatherproofing and positive drainage.
We review our drawings carefully before submission to minimize correction requests. For hillside lots or projects with unusual structural conditions, we engage a structural engineer during the design phase to ensure the plans will pass review before submission, rather than learning about problems during review.
What Happens If You Build Without a Permit?
Building without a required permit creates a documented code violation that stays with the property — not with you personally — for as long as the structure exists.
When you sell your home, Washington State disclosure requirements require sellers to disclose known unpermitted structures. Buyers' lenders frequently flag unpermitted structures during the appraisal process, which can complicate financing or require remediation — at the seller's expense — before closing. We've seen transactions delayed or derailed entirely by unpermitted decks discovered during inspection.
In more serious cases, code enforcement can issue an order requiring you to obtain permits retroactively. This sometimes means exposing framing for inspection after the fact, potentially removing the deck surface to allow inspection of the structural components. For structures that cannot be permitted as-built due to code violations in the existing construction, the order may require demolition.
Beyond the legal and financial exposure, there's a safety dimension. The footing, framing, and ledger inspections that happen during a permitted build exist because these are the components most likely to cause catastrophic failure if built incorrectly. A deck collapse during a family gathering is statistically most likely when those structural details were never reviewed by an inspector.
How We Handle Permits for Every Project
We handle the full permit process as part of every project we take on. We identify the correct jurisdiction for your property, coordinate or produce the required structural drawings, submit the permit application, respond to any plan review correction letters, schedule and attend required inspections, and close out the permit after final inspection.
Permit timeline is the primary reason we recommend starting the planning process earlier than most homeowners expect. If you want to build in May, you need to be submitting your permit application in February — because a standard three-to-eight-week plan review doesn't fit into a "we want to start in two weeks" schedule. See our related article on the best time to build a deck in Seattle for more on planning around permit timelines.
Ready to get your project permitted and on the calendar? Call (425) 675-6259 or [request a free quote](/contact). We'll assess your site, identify the permit requirements for your jurisdiction, and give you an honest timeline for getting ground broken.