Do I Need a Permit for a Deck?

Most decks need a building permit. Decks carry people, sit on footings that can heave or settle, and are often bolted to the side of a house, so building departments treat them as structures rather than as landscaping. The model code most US jurisdictions start from, the International Residential Code (IRC), carves out only a narrow exemption for small, low, freestanding decks.

The details matter because states and cities adopt the IRC with their own amendments. Some remove the deck exemption entirely, some shrink it, and a few have additional rules for decks in coastal, wildfire, or flood areas. Use this guide to understand the typical rules, then confirm with your local office. If you don’t know which office covers your address, you can find your local building department.

What the model code exempts

Section R105.2 of the 2021 IRC lists work that does not need a building permit. The deck exemption is Building item 10, and it applies only when all of these are true:

• The deck is 200 square feet or less in area.
• No point of the walking surface is more than 30 inches above grade.
• The deck is not attached to the dwelling.
• The deck does not serve the exit door the code requires for the house.

Miss any one of these and the model code expects a permit. The construction rules for decks are in IRC Section R507, and guard and stair rules are in Sections R312 and R311. The code also says that an exemption from a permit does not exempt the work from meeting the code, so an exempt deck still has to be built safely and comply with zoning.

When you usually need a permit

Expect to need a permit if your project involves any of the following:

• A deck attached to the house with a ledger board, regardless of size or height.
• Any deck larger than 200 square feet, even if it sits close to the ground.
• Any deck with a walking surface more than 30 inches above grade at any point, which also triggers guard (railing) requirements.
• A deck that serves as the landing for the home’s required exit door.
• Adding a roof, pergola, screen enclosure, or hot tub to a deck, all of which change the loads.
• Replacing structural members such as posts, beams, joists, footings, or the ledger.
• Adding stairs, or rebuilding stairs and guards.
• Wiring outlets or lighting, or running a gas line for a grill or fire feature (these usually need separate electrical or mechanical permits).

Work that is often exempt

Depending on local rules, these are commonly allowed without a building permit:

• Small, low, freestanding decks that meet all four conditions above.
• Replacing deck boards in kind, without touching the framing.
• Staining, sealing, or painting an existing deck.
• Ground-level patios of pavers or concrete, which the model code treats like sidewalks.

“Often exempt” is not the same as “always exempt.” Some cities require a permit for any deck, and some require a zoning permit even when no building permit is needed.

What the inspection covers

Deck inspections focus on the parts that fail: footings, the ledger connection, and guards. A typical sequence looks like this:

1. Footing inspection. Before concrete is poured, the inspector checks hole depth and diameter. The model IRC requires deck footings at least 12 inches below undisturbed ground (R507.3.2), and a deck attached to a frost-protected house must also have frost-protected footings, typically below the local frost line (R507.3.3). R507.3 waives footings for some small freestanding decks, such as one of 200 square feet or less whose joists bear directly on precast pier blocks with the walking surface no more than 20 inches above grade.
2. Framing inspection. Before decking goes on, or before the underside is closed in, the inspector checks post size and height, beam spans, joist size and spacing, hangers and fasteners, and the ledger. Attached decks must be positively anchored to the house for vertical and lateral loads, and toenails or nails subject to withdrawal are not allowed for that connection (R507.8). Inspectors look for galvanized or stainless lag screws or bolts into the house’s band joist (R507.9.1.3), flashing to keep water out of the house wall, and, where used, lateral load hold-downs (R507.9.2). Ledgers may not be supported on stone or masonry veneer (R507.9.1.1).
3. Final inspection. The inspector checks guards, stairs, handrails, and the finished surface.

Under the model IRC, guards are required on open sides more than 30 inches above the floor or grade below (R312.1.1), must be at least 36 inches tall (R312.1.2), and must not allow a 4-inch sphere to pass through (R312.1.3). Stair risers can be no more than 7 3/4 inches (R311.7.5.1) and treads at least 10 inches deep (R311.7.5.2), and a flight with four or more risers needs a handrail (R311.7.8). Many departments refer builders to the American Wood Council’s prescriptive deck guide (DCA 6), which turns the code’s requirements into span tables and connection details for typical wood decks.

Ask your department whether inspections must be scheduled in a particular order, and whether you can photograph footings instead of waiting for an inspector. Some offices allow that for small projects; many do not.

How the rules differ by city

The IRC exemption is only a starting point. These jurisdictions show how far local rules can move it:

• Seattle requires a permit for any deck more than 18 inches above the ground, a roof deck, or a deck in an environmentally critical area such as a landslide-prone or flood-prone site, according to SDCI’s deck page. Most decks need only a subject-to-field-inspection permit. Decks more than 18 inches high also have to meet zoning setbacks.
• Denver splits the decision between zoning and building. Uncovered decks 12 inches or less off the ground need no permit unless the property is a landmark or in a historic district. Decks more than 12 inches up need a zoning permit, decks 30 inches or more up also need a building permit, and every covered patio, porch, or pergola needs both.
• Austin follows the IRC exemption but adds a condition: the deck cannot be in a flood hazard area. Austin also exempts non-structural repairs limited to the existing deck boards, as long as they don’t include guardrails or handrails.
• Fairfax County, Virginia lists decks under “new addition to an existing home” on its list of projects that require a permit. The county publishes Typical Deck Details for single-level decks, based on the 2021 Virginia Residential Code; builders record their design in the document, keep it on site for each inspection, and need county approval to deviate from it. Those details call for footings bearing on solid ground 24 inches below grade.
• Phoenix charges building permits by project valuation. Under the PDD fee schedule effective January 20, 2026, a residential project valued from $1,001 to $10,000 pays $195 for the first $1,000 plus $12 for each additional $1,000, with plan review billed separately as a percentage of the permit fee.

What to have ready when you apply

Applications for a residential deck typically ask for:

• A site plan showing the lot lines, the house, the deck footprint, and distances to property lines, easements, and other structures.
• Framing plan. Joist size, spacing, and direction; beam size and spans; post sizes and locations; and footing sizes and depth.
• Ledger and connection details, including fastener type and spacing and how the ledger is flashed.
• Elevation or section drawing showing deck height above grade, guard height, and stair dimensions.
• Material specifications, especially for composite decking, which must be installed according to the manufacturer’s listing and span ratings.
• Contractor information if you are hiring one, including any state or local license number.

Before you submit, work through this short list:

• Confirm whether your deck is exempt under your city’s version of R105.2, including height, size, attachment, and flood-zone conditions.
• Check zoning setbacks and lot coverage for your lot.
• Ask whether the department accepts its own prescriptive details or DCA 6 in place of custom plans.
• Call 811 before digging footings.
• Line up separate electrical, gas, or plumbing permits if the deck includes lighting, a grill line, or a hot tub.
• Schedule the footing inspection before you pour concrete.

Many departments publish a deck handout or sample drawing that shows exactly what they want. Ask for it before you draw your own plans. It often answers questions about footing depth, approved ledger fasteners, and whether a plan reviewer will accept DCA 6 details as-is.

Zoning and HOA rules are separate

A building permit confirms the deck is built safely. Zoning rules control where it can go, and they apply even to decks that are exempt from a building permit. Check these before you finalize a design:

• Setbacks. Decks usually have to stay a set distance from rear and side property lines. Some codes allow low decks to encroach into setbacks while higher decks cannot.
• Lot coverage limits, which may count decks.
• Easements. Utility and drainage easements commonly prohibit permanent structures.
• Historic districts that review visible exterior changes.
• Floodplain rules if your lot is in a mapped flood hazard area.
• HOA covenants, which can restrict size, materials, and colors and often require written architectural approval before you start.

Before digging footings, contact 811 so utilities can mark buried lines. The service is free and is required in many states before excavation.

Hiring a contractor vs doing it yourself

Most jurisdictions allow homeowners to pull their own permit for a deck on a home they own and occupy. You take on responsibility for meeting code and scheduling inspections. See our guide to owner-builder permits for the common conditions and limits.

If you hire a contractor, the contractor normally pulls the permit. Ask to see it before work starts, and confirm that the final inspection passed before you make the last payment. Some states require licensing for residential contractors above a dollar threshold, and electrical or gas work on a deck may require a licensed trade regardless of who builds the framing.

Questions to ask your building department

• Does the city follow the IRC deck exemption, or does every deck need a permit?
• What frost depth do footings need to reach?
• Which inspections are required, and how do I schedule them?
• Is there a deck handout or prescriptive plan I can use?
• Does a zoning review happen with the building permit, or separately?
• Do I need separate permits for electrical, gas, or a hot tub?

If you have already built a deck without a permit, it is usually better to approach the department about a retroactive permit than to wait for it to surface during a sale. Our guide to unpermitted work explains how that process typically works, and building inspection stages covers inspections in more detail.