Deck Permit in Thurston County, Washington
By Mario Bailey Last checked 2026-07-19 · 2 official sources
Verified against official sources Confirmed on official pageIt depends
Quick answer
Decks 30 inches or less from the ground to the top of the deck are exempt from a county building permit. Taller decks require a residential building permit through the Building Development Center using the Residential Building Permit Application.
Typical threshold: Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck.
Who is pulling this permit?
Apply yourself
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Before you sign, ask the contractor:
- Who pulls the permit, you or me, and is the permit fee included in the bid?
- Which inspections will this job need, and who meets the inspector on site?
- Is your contractor license active in this locality, and under which business name?
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When a permit is usually needed
Decks more than 30 inches above the ground
What your deck permit must meet in Washington
A residential deck in Washington is built to the 2021 International Residential Code as adopted with state amendments (WAC 51-51, Washington State Residential Code 2021), which among other things raises the deck live load to 60 psf. The prescriptive deck rules cover guards, stairs, footings, and a positive ledger and lateral-load connection.
- Guards are required whenever the deck walking surface is more than 30 inches above the grade or floor below (R312).
- Required deck guards must be at least 36 inches high, with openings sized so a 4-inch diameter sphere cannot pass through (R312).
- Deck stairs (any flight with 4 or more risers) allow a maximum riser height of 7 3/4 inches, require a minimum tread depth of 10 inches, and a minimum stairway width of 36 inches (R311.7).
- Stairs with 4 or more risers need a handrail on at least one side, with the top 34 to 38 inches above the stair nosing (R311.7.8).
- Exterior footings must be placed at least 12 inches below undisturbed ground (R403.1.4); frost-protection depth is not a single statewide number but is set by the local jurisdiction, so confirm frost depth with the local building department (R403.1.4.1).
- The deck ledger must have a positive connection to the band joist using lag screws or bolts spaced per Table R507.9.1.3, not toenails or deck screws, and the band joist must be minimum 2-inch nominal solid-sawn lumber or engineered rim board (R507.9).
- A lateral load connection is required: hold-down tension devices in at least two locations per deck, each with a capacity of not less than 1,500 pounds (R507.9.2).
Based on Washington State Residential Code 2021 (2021 IRC with WA amendments, WAC 51-51): R312, R311.7, R403.1.4, R507.9. Read the code. Local amendments can be stricter; confirm the current requirement with your office before you build.
What deck permit costs in Thurston County
Building permit and plan review fees are valuation based; see the county 2026 Residential Building Fee Guide.
How Thurston County compares in Washington
Across the Washington jurisdictions we have verified, the same threshold runs from 18 to 30, so a project that is exempt here may still need a permit one county over.
| Jurisdiction | Permit needed? | Threshold |
|---|---|---|
| Bellevue | It depends | decks where the highest walking surface is 30 inches or less above grade do not require a permit; decks over 30 inches above grade require a permit with plan review |
| Clark County | It depends | Exempt only if the deck does not exceed 200 square feet, is not more than 30 inches above grade at any point, is not attached to a dwelling, does not serve a required exit door, and is not used for a hot tub or pool; all other decks require a permit. |
| King County | It depends | uncovered decks 30 inches or less above ground do not require a building permit in unincorporated King County; decks over 30 inches above grade require a permit |
| Pierce County | It depends | Decks not more than 30 inches above grade at any point, and not over any story or basement below, are exempt; Pierce County code sets no separate floor area cap for decks; taller decks, or decks over a story or basement, require a building permit. |
| Seattle | It depends | decks more than 18 inches above grade require a permit; decks 18 inches or less above grade and not over a basement do not require a permit |
| Snohomish County | It depends | uncovered decks, deck steps, and uncovered porches for residential buildings exempt if 30 inches or less above adjacent grade at any point, not over a basement or story below, and not part of a required accessible route; covered or taller decks require a permit |
| Thurston Countythis page | It depends | Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck. |
Closest deck permit thresholds outside Washington
Jurisdictions we cover whose limit sits nearest Thurston County's 30 inches.
- Peoria, Arizona, Platforms not more than 30 inches above adjacent grade that are not over a basement or story below and are not part of an accessible route are exempt from a permit.
- Miami-Dade County, Florida, wood deck 18 inches or less above ground is exempt; decks higher than 18 inches require a building permit
- Prince William County, Virginia, building permit required if deck floor is 16.5 inches or more above finished grade
How to apply in Thurston County
A residential deck permit application is a set of construction documents that show what will be built and prove it meets the IRC deck provisions. In practice that means a scaled site plan locating the deck and its setbacks, plus deck plans and structural details covering the footings, posts, beams, joists, ledger, guards, and stairs.
What most deck permit applications include:
- A permit application identifying the work, the deck's size (square footage), and whether electrical work such as lights or receptacles is included, submitted for plan review before construction begins (IRC R106).
- A scaled site plan (for example 1/4 inch to 1 foot) showing the new deck's location relative to the house, its overall length and width, and dimensioned distances from the deck to all property lines and other structures so required setbacks can be verified (IRC R106.1.1).
- A deck plan drawn to scale showing overall dimensions and the framing layout: joist size, spacing, span, and species; beam size and span; post size and height; and footing or pier size and depth (IRC R507.4 posts, R507.5 beams, R507.6 joists, R507.3 footings).
- A section or side elevation with connection details showing the ledger attachment to the house band joist with flashing, the fastener or bolt schedule, joist hangers, post-to-beam and post-to-footing connections, and the required lateral load connection (IRC R507.9 ledger connection, R507.9.2 lateral connection, R507.2.4 flashing).
- Footing sizing derived from tributary area, the soil bearing value, and design loads per IRC Table R507.3.1, with footings shown bearing on undisturbed soil at the frost depth required by the jurisdiction (IRC R507.3).
- Details for the guards required where the walking surface is more than 30 inches above grade, and for the stairs and handrails, showing guard height and opening limits, stair riser and tread dimensions, and handrail location (IRC R312 guards, R311.7 stairs and handrails).
- For designs that fall outside the prescriptive R507 tables (for example multi-story or stacked decks, or a ledger attached to a cantilever), engineered and stamped structural plans are submitted in place of the prescriptive details (IRC R507.1 and R301).
General submittal guidance from IRC R106.1.1 (construction documents) and IRC R507 (exterior decks), 2021 IRC. Source. Community Planning and Economic Development - Building Development Center sets the exact checklist for Thurston County.
Where to apply in Thurston County:
Community Planning and Economic Development - Building Development Center
- 3000 Pacific Ave SE, Suite 100, Olympia, WA 98501
- Phone: 360-786-5490
- Email: permit@co.thurston.wa.us
Inspections and closing out your permit
Deck work is inspected in sequence as it is built: the footings before concrete is placed, the framing before the decking boards go down, and a final inspection once the deck is complete. Each stage checks the items that would be hidden or unsafe if missed.
- Footing or pier inspection: after the holes are dug and any forms or reinforcing are set but before concrete is placed, the inspector checks footing depth and diameter, a flat undisturbed bearing surface, and that the holes are free of water (IRC R109.1.1 foundation inspection; R507.3 footings).
- Framing inspection: after the deck is framed but before the decking conceals it, the inspector verifies the ledger attachment and its flashing, the fastener and bolt schedule, joist hangers and metal connectors, post-to-beam and post-to-footing connections, and the lateral load connection; call it before decking is installed (IRC R109.1.4 frame inspection; R507.9 ledger and flashing).
- Final inspection: after the deck is complete and before it is used, the inspector confirms guard height and opening limits (a 4 inch sphere must not pass, 4 3/8 inch at stairs), stair riser and tread dimensions, handrail height and graspability where there are 4 or more risers, stair landings, and required stair lighting (IRC R109.1.6 final inspection; R312 guards, R311.7 stairs and handrails).
Schedule each inspection in advance and pass the final before you use the work or close the permit. Request inspections through the Thurston County permit portal or by phone at 360-786-5490.
Inspection sequence from IRC R109 (inspections: R109.1.1 footing before concrete, R109.1.4 frame, R109.1.6 final), 2021 IRC. Source. An open permit left un-inspected can surface later in a title search or home sale.
Your Deck Permit checklist for Thurston County
- Confirm the requirement. Sometimes, depending on the project. Typical threshold: Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck. Usually needed: Decks more than 30 inches above the ground.
- Budget the fee. Building permit and plan review fees are valuation based; see the county 2026 Residential Building Fee Guide. Official fee schedule.
- Apply. A residential deck permit application is a set of construction documents that show what will be built and prove it meets the IRC deck provisions. In practice that means a scaled site plan locating the deck and its setbacks, plus deck plans and structural details covering the footings, posts, beams, joists, ledger, guards, and stairs. Start at the Thurston County permit portal.
- Keep the office details handy. Community Planning and Economic Development - Building Development Center. Phone: 360-786-5490. Address: 3000 Pacific Ave SE, Suite 100, Olympia, WA 98501.
- Plan for inspections. Deck work is inspected in sequence as it is built: the footings before concrete is placed, the framing before the decking boards go down, and a final inspection once the deck is complete. Each stage checks the items that would be hidden or unsafe if missed.
Compiled from the official sources on this page. Last checked 2026-07-19.
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Frequently asked questions
- Do you need a deck permit in Thurston County?
- Decks 30 inches or less from the ground to the top of the deck are exempt from a county building permit. Taller decks require a residential building permit through the Building Development Center using the Residential Building Permit Application. Decks are exempt if the surface is 30 inches or less from the ground to the top of the deck. Always confirm with the office before starting.
- How much does a deck permit cost in Thurston County?
- Building permit and plan review fees are valuation based; see the county 2026 Residential Building Fee Guide. See the official fee schedule for current amounts.
- Where do you apply for a deck permit in Thurston County?
- You can apply through the Thurston County permit portal or contact the Community Planning and Economic Development - Building Development Center directly. The links are listed on this page.
From the Library
What else needs a permit in Thurston County
Every other permit type we have verified for this jurisdiction, with the rule that applies here.
| Project | Permit needed? | Threshold | Typical fee |
|---|---|---|---|
| Electrical Permit | Permit required | Electrical work in unincorporated Thurston County requires a state electrical permit from L&I; the county itself does not issue electrical permits, with limited work exceptions under WAC 296-46B-901. | L&I sets electrical permit fees; |
| Fence Permit | It depends | Fences 8 feet tall or shorter are exempt from a county building permit. | Building permit and plan review fees are valuation based; |
| HVAC Permit | It depends | Heating and cooling equipment and gas piping require a Minor Permit, but replacement of electric forced-air heating units and water heaters is exempt. | Minor Permit fees apply; |
| Patio Permit | It depends | Patios and porches are exempt if 30 inches or less from the ground to the top of the surface. | Building permit and plan review fees are valuation based; |
| Plumbing Permit | Permit required | No permit is needed only to clear a blockage or to repair or stop a leak in a drain, water, soil, or vent pipe. | Minor Permit fees apply; |
| Pool Permit | It depends | Pools are exempt only if prefabricated, entirely above ground, less than 24 inches deep, and under 5,000 gallons capacity. | Building permit and plan review fees are valuation based; |
| Roof Replacement Permit | It depends | Roof repair and replacement is exempt unless the work adds skylights or changes, repairs, or replaces structural elements or the roof pitch or slope. | Building permit and plan review fees are valuation based; |
| Shed Permit | It depends | One-story detached accessory buildings with no plumbing or electricity are exempt if under 200 square feet inside a county urban growth area or under 400 square feet outside a UGA. | Building permit and plan review fees are valuation based; |
| Solar Permit | It depends | Residential rooftop solar PV systems need no county permit; ground-mounted and commercial systems require county permits, and every solar project needs a state L&I electrical permit. | Building permit and plan review fees are valuation based; |
Deck Permit in other Washington localities
Official sources
- https://www.thurstoncountywa.gov/departments/community-planning-and-economic-development/permitting/permits-fees-forms/do-you-need-permit
- https://www.thurstoncountywa.gov/departments/community-planning-and-economic-development/permitting/permits-fees-forms/permit-applications-forms
- https://www.grafton-ma.gov/DocumentCenter/View/17797/2021-IRC-Residential-Deck-Guide
- https://www.spearfish.gov/DocumentCenter/View/5233/Residential-Deck-handout-PDF
- https://www.co.pacific.wa.us/dcd/images/apps-forms/Deck%20Handout-final.pdf
Verified by a person against the sources above on 2026-07-19, not confirmed with Community Planning and Economic Development - Building Development Center. Rules change; confirm before you build. How we verify.
Last checked: 2026-07-19Report an error on this page
Compare Deck Permit requirements across Washington localities
Permit office
Community Planning and Economic Development - Building Development Center
360-786-5490Permit portalWashington rule changes
- Bellevue, WA sets a flat $290 re-roof permit fee (Ordinance 6879)
Ord. 6879 · 2026-07-25