Fees
Estimated city fees
Baseline for a simple permitted deck: $175–$550 estimated combined fees (permit + plan review) for a typical permitted residential deck in St. Louis
| Fee | Amount | Notes |
|---|---|---|
| Building permit fee | $100–$350 (estimated, based on construction valuation) | The St. Louis Building Division calculates permit fees by declared project valuation. A typical residential deck valued at $8,000–$20,000 generally falls in this range. Verify the current fee schedule at stlouis-mo.gov/government/departments/public-safety/building-division. |
| Plan review fee | $75–$200 (estimated) | Plan review for residential projects is typically assessed as a separate fee based on project valuation. Simple, standard-size decks may qualify for expedited review. |
| Inspection fees | Included with permit | Required inspections (footing, framing, final) are covered under the permit fee. A re-inspection fee applies if work is not ready or fails inspection. |
Documents
Required documents
- Building permit application submitted through the City of St. Louis Building Division (in-person at 1200 Market St., Room 425, or via the city online portal).
- Site plan drawn to scale showing property lines, existing structures, proposed deck footprint, setback dimensions, and distance to property lines.
- Construction drawings showing deck dimensions, height above finished grade, framing layout, footing design, beam and joist schedule, ledger connection detail with flashing for attached decks, and railing/stair details.
- Footing design documentation showing footings extend to the frost depth (minimum 30 inches below grade) as required by the 2018 IRC with St. Louis cold-climate amendments.
- Zoning verification from the City of St. Louis Zoning Section confirming compliance with applicable yard setbacks and lot-coverage limits.
- Contractor license documentation if a contractor applies on behalf of the homeowner, or owner-builder authorization for self-performed work.
Timeline
Typical timing
- Plan review
- 10–20 business days
- Total cycle
- 5–8 weeks from application to final inspection
Historic district review, floodplain overlay conditions, and correction cycles can extend the timeline. St. Louis Building Division workload varies seasonally.
Affiliate slot
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Contextual referral placement for Angi / HomeAdvisor style contractor matching.
Process
How the permit process works
- Determine whether a permit is required Confirm whether the deck is attached to the house, exceeds 30 inches above grade, or exceeds 200 square feet as a freestanding structure. If any condition applies, a building permit is required. Contact the St. Louis Building Division at 314-622-3313 if you are close to a threshold.
- Check zoning and setback requirements Use the City of St. Louis zoning map or contact the Zoning Section to confirm required setbacks for your zoning district. Decks must respect front, rear, and side yard setbacks. Lot coverage limits may also apply depending on your zone.
- Prepare plans with frost-depth footing design Draw up a site plan and construction drawings per the 2018 IRC with St. Louis amendments. Footings must extend to the frost depth (30 inches minimum) to prevent frost heave common in St. Louis winters. Include ledger connection detail with flashing if the deck is attached to the house.
- Submit permit application to the Building Division Submit your application, plans, and supporting documents in person at the St. Louis Building Division, 1200 Market St., Room 425, or through the city's online permit portal. Bring two sets of plans for larger projects.
- Complete plan review and respond to corrections Building Division plan examiners review the submittal against the 2018 IRC and St. Louis local amendments. If correction items are noted, update drawings and resubmit. Simple residential decks often receive approval within 10–15 business days.
- Pay fees and receive the permit Once plan review is approved, pay the remaining permit fees. Keep the issued permit and approved plans at the job site during all construction phases as required by Missouri law.
- Schedule required inspections Request inspections through the Building Division inspection scheduling system. Required inspections include a footing inspection before pouring concrete (to verify frost depth), a framing inspection after structural members are in place but before covering, and a final inspection upon completion.
- Pass final inspection and close the permit After final inspection sign-off, the permit is closed and the deck becomes part of the official City of St. Louis building record. This protects you at resale, for insurance, and on future permit applications.
Code basis
What St. Louis reviews against
2018 International Residential Code (IRC) with City of St. Louis local amendments, administered by the St. Louis Building Division.
If you skip the permit
What can go wrong
- The St. Louis Building Division can issue a stop-work order if unpermitted construction is discovered, halting all work immediately.
- The city may require demolition or structural opening of an unpermitted deck at the owner's expense to verify structural compliance.
- Daily civil penalties and fines can accrue under St. Louis City Code until the violation is resolved.
- Frost-heave damage from improperly depth footings — a common failure mode in St. Louis winters — goes undetected without permit inspection, creating structural and safety risks.
- Unpermitted work must typically be disclosed in Missouri real estate transactions and can complicate or delay a sale.
- After-the-fact permits in St. Louis carry penalty fees and typically require invasive inspection of existing work.
Affiliate slot
What you’ll need for the project
Contextual Amazon-style tools and materials block for deck projects.
FAQ
Common St. Louis deck permit questions
Do I need a permit to build a deck in St. Louis, MO?
Usually yes. A building permit is required for any deck attached to the house and for any freestanding deck that is more than 30 inches above grade or larger than 200 square feet. A small freestanding deck within those thresholds may not require a permit, but City of St. Louis zoning setbacks still apply. When in doubt, contact the St. Louis Building Division before starting work.
What building code does St. Louis use for decks?
The City of St. Louis administers the 2018 International Residential Code (IRC) with local St. Louis amendments. Deck framing must comply with IRC Section R507 (Exterior Decks) and applicable structural chapters. A key local requirement is frost-depth footings — footings must extend at least 30 inches below grade to prevent frost heave during St. Louis winters.
How much does a deck permit cost in St. Louis?
Estimated combined fees (permit plus plan review) for a typical residential deck in St. Louis run approximately $175–$550, based on project valuation. Actual amounts depend on the declared construction value. Verify the current fee schedule with the St. Louis Building Division at stlouis-mo.gov/government/departments/public-safety/building-division.
Where do I apply for a deck permit in St. Louis?
Submit in person at the City of St. Louis Building Division, 1200 Market St., Room 425, St. Louis, MO 63103, or through the city's online permit portal. The Building Division is open weekdays and can be reached at 314-622-3313.
What footing depth is required for a deck in St. Louis?
Footings must extend below the frost line, which is approximately 30 inches in the St. Louis area. This is required by the 2018 IRC and St. Louis local amendments to prevent frost heave — seasonal ground freezing and thawing that can shift shallow footings and damage the deck structure. The footing inspection verifies depth before concrete is poured.
What inspections are required for a deck permit in St. Louis?
A typical St. Louis residential deck permit requires a footing inspection before pouring concrete (to verify frost depth), a framing inspection after structural members are installed but before covering, and a final inspection upon completion. Your permit documentation will list the specific inspections required for your project.
Does St. Louis have net metering for solar — and how does it relate to my deck project?
Yes. Missouri requires 1:1 net metering under state law (RSMo Section 393.320), and Ameren Missouri honors this for systems up to 100 kW — unusually generous compared to many states. If you are building a deck and also considering rooftop solar, Missouri's strong net metering framework provides better long-term economics than states that have moved to lower avoided-cost export rates. See the St. Louis Solar Savings Calculator for Ameren Missouri rate and payback details.
Sources
Official links and freshness
- https://www.stlouis-mo.gov/government/departments/public-safety/building-division/
- https://www.stlouis-mo.gov/government/departments/public-safety/building-division/permits/index.cfm
- https://codes.iccsafe.org/content/IRC2018
- https://www.stlouis-mo.gov/government/departments/planning/zoning/
- https://revisor.mo.gov/main/OneSection.aspx?section=393.320
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Disclaimer: This page is informational, not legal advice. Permit rules, fees, and processes change. Verify your project with St. Louis permitting staff before building.