The short answer
Under the model code, most decks need a permit. The model code exempts only a deck of 200 sq ft or less, no more than 30 in above grade, not attached to a dwelling and not serving the exit door, and a deck must meet all four at once. Many states and counties change or drop that exemption, so your building department has the final word.
If you are reading about deck permit requirements, you probably want one answer: do I need one? Most of the time, yes. The model building code lets you skip a permit for only a small, low, detached deck, and many states and counties are stricter than the model. This guide gives you the model rule, the things that cancel it, a table of what we found for a set of states, and the list of drawings a reviewer asks for.
We cite official pages and say when we only saw a summary of a page. Where we have no source for a place, the table says to check with your building department, because a guess here could cost you a stop-work order.
Do I Need a Permit for a Deck?
Start with the model code, since most local rules are copies of it with changes. Section R105.21 of the 2021 International Residential Code lists work that needs no permit. One item covers decks.
The model exemption: four conditions at once
The wording we read in a county copy of R105.21 exempts decks not exceeding 200 sq ft, no more than 30 in above grade at any point, not attached to a dwelling, and not serving the exit door required by section R311.4. That is four conditions, not one, and a deck must meet all of them. A 150 sq ft deck bolted to the house wall is not exempt. A freestanding 120 sq ft deck 3 ft off the ground is not exempt either.
Exempt does not mean code-free
The same model section says an exemption does not grant authority to do work in violation of the code or of other laws. So even a deck that needs no permit has to be built to the code, and it still has to respect setbacks and any other local rule. If an inspector never sees it, the rules still apply.
It is only a default
Treat 200 sq ft and 30 in as the model’s starting point and not as a national law. Montgomery County, Maryland, for example, replaced that wording with its own, and Nashville says any new deck needs a permit. The table below shows how far the answers drift.
- 1Grant County, Washington Exempt R105.2 (2021 International Residential Code, section R105) (2021)
What Still Triggers a Permit
Even if you are close to the model numbers, a few features push a deck into permit territory in most places. Check each one against your plan.
Attached to the house
A deck with a ledger fastened to the house is attached, and the model exemption does not cover it. The ledger is also where the code is strictest: it must be flashed, fastened on a schedule and kept off some wall types. The deck ledger board guide covers those rules, and the DCA62 guide prohibits a ledger on brick or stone veneer.
Height above 30 in
The model exemption stops at 30 in above grade, measured at any point. The code uses the same 30 in as the point where a 36 in guard is required. A guard has its own rules, a 4 in sphere limit on openings and a 200 lb load at the top rail, and a reviewer wants to see them on the guard detail sheet.
Stairs and landings
Stairs add their own checks: riser height of 7-3/4 in or less, tread of 10 in or more, a width of at least 36 in, and a landing when the total rise passes 12 ft. A handrail is required once a stair has four or more risers. If your deck needs more than a step or two, expect the reviewer to look at the stair sheet. Our deck stairs guide gives the full set of numbers, and if you are adding a pergola, see the pergola permit guide.
Setbacks and HOA rules
A permit-free deck can still break a setback from the property line, an easement or a utility. Those are zoning questions, and the building department may not answer them. A homeowners association can also demand its own approval whether or not the county wants a permit. This is our editorial advice, not a code rule: check both before you buy lumber.
- 2American Wood Council Prescriptive Residential Wood Deck Construction Guide (DCA 6, 2015 IRC version) (2015)
Deck Permit Requirements by State
The table covers ten states, ordered by how often people search for each state’s deck permit rules. We checked the pages named in the last column in November 2026. Where we saw only a search summary of a page, the row says so. Where a cell says “check with your building department,” we did not find an official sentence to quote and we are not guessing.
A short note on reading it: the code edition tells you which version of the model rules a state starts from, “who decides” tells you who issues the permit, and the exemption column quotes or summarizes what the official page says about decks.
| State | Code edition | Who decides | Deck exemption as written | Official page |
|---|---|---|---|---|
| California | 2025 California Residential Code, effective January 1, 2026 for applications filed on or after that date | Local building department (not confirmed on an official page) | Check with your building department | DGS code changes page |
| Massachusetts | 780 CMR 10th edition, based on the 2021 IRC | Municipal building official | The state’s licensing chart lists decks as needing a building permit, and patios as not. The chart is “for general guidance only,” so consult your building official | Mass.gov contractor resources |
| Florida | 8th edition (2023) Florida Building Code, per a summary we saw | Local jurisdictions (not confirmed on an official page) | Check with your building department | FBC analysis of changes |
| Tennessee | No single statewide deck rule found | Local, so it varies by city and county | Nashville: “Replacement of a deck or construction of a new deck requires a permit.” Knoxville and Shelby County pages appear to show the model 200 sq ft wording, but we saw only search summaries | Nashville add-a-deck page |
| Indiana | 2020 Indiana Residential Code (675 IAC 14-4.4), per a summary, with the rules under readoption | State writes the code, local units issue permits | Check with your building department. One city, Greenwood, says anything bigger than 3 ft by 3 ft needs a permit, per a search summary | Indiana Fire Prevention and Building Safety Commission rules |
| Kentucky | 2018 Kentucky Residential Code (3rd edition, August 2024), based on the 2015 IRC | State code, but permits for a single-family dwelling only if local ordinance requires them | The regulation says permits, inspections and certificates “shall not be required for a single-family dwelling unless required by local ordinance.” A code summary shows the model 200 sq ft / 30 in wording, which we did not open | 815 KAR 7:125 |
| Texas | Houston: 2021 IRC with local amendments | City of Houston (statewide position not checked) | Houston keeps the model item: decks not exceeding 200 sq ft, not more than 30 in above grade at any point, not attached to a dwelling and not serving the exit door | Houston amendments PDF |
| Virginia | 2021 Virginia Uniform Statewide Building Code, last amended January 18, 2024 | Local building official | Section 108.2 lists the work that is exempt, and no deck is on that list | 13VAC5-63-80 |
| Maryland | Montgomery County: 2021 IRC, mandatory from March 31, 2025, per a county summary | County permitting department | The county page says it replaced the 200 sq ft / 30 in wording with “decks where the joists bear completely on grade, supporting no other structures,” per our reading of its summary | Montgomery County residential decks |
| Michigan | 2015 Michigan Residential Code, per a summary | State, county or local unit, per the LARA jurisdiction list | Check with your building department. A proposed 2021 rule notice carries the 200 sq ft wording, but we could not confirm it is in force | LARA building permit information |
What the table shows
Three patterns stand out. Some places copy the model exemption (Houston). Some drop it or say nothing about decks in the exempt list (Virginia, Nashville, Massachusetts). And Montgomery County writes a different test. So you cannot carry a rule from a blog about another state.
Virginia, Massachusetts and Michigan in plain terms
Virginia’s state code lists sixteen kinds of exempt work, among them fences, small detached sheds and walls up to 6 ft, and a deck is not one of them. A new deck therefore falls under the general rule that building a structure needs a permit. We did not find the “30 in freestanding” exemption that some third-party pages claim in the state text.
Massachusetts publishes a chart where decks need a building permit and a Construction Supervisor License for new construction, while patios do not. Michigan asks for a set of construction documents with each application. For a one- or two-family dwelling under 3,500 sq ft, the state does not require an architect or engineer seal on those documents, which matters if you plan to use an unstamped set. Your local office may still have its own rules.
Tennessee and Kentucky in plain terms
In Tennessee the answer changes by city: Nashville wants a permit for any new deck, and a board replacement above 100 sq ft also needs one, while tearing a deck down needs none. Kentucky leaves permits for single-family homes to local ordinance, so a county without one may ask nothing, while a city may ask for a lot. Call before you assume.
Depends on where you build
Your state or county may not be on this list
We did not research every state. If yours is missing or says “check with your building department,” search for “[your city] deck permit” and read the building department’s own page, not a contractor’s summary. Then ask which code edition they follow and which sheets they want.
What the Permit Office Asks For
Most offices ask for an application, a site plan and construction drawings. The exact list is on the department’s page or a deck handout, and some counties give a one-page checklist.
The usual sheets
A typical set has a site plan, a framing plan, a footing plan, a ledger and flashing detail, a lateral load detail, an elevation, a guard detail and a stair detail. Each member needs its size written on the sheet. Our deck drawings for permit guide goes through all eight.
Ledger and lateral details
If the deck attaches to the house, expect the reviewer to look for the ledger fasteners, the flashing and the lateral hold-downs. The DCA62 guide asks for two hold-down devices rated at least 1,500 lb within 2 ft of the deck edges on an attached deck. The DCA6 explained guide shows where those rows live.
The site plan
Nashville asks for the application plus a site plan with distances to property lines, structures and easements. Other offices ask for the same thing in different words. Measure from the house to each lot line, and mark the deck and any existing sheds, so the reviewer can see the setbacks.
Try it
See what a reviewer reads
Once you know what your office wants, open the sample sheets in deck drawings for permit and the list of what you supply yourself.
- 2American Wood Council Prescriptive Residential Wood Deck Construction Guide (DCA 6, 2015 IRC version) (2015)
Built Without a Permit
If a deck is already built without one, check your local rules before you do anything else. We have not researched penalties by state and we will not invent any.
What can happen
The general outcomes are things like a stop-work order, a fee to permit the work after the fact, or a request to open parts of the deck for inspection. A missing permit can also surface when you sell or file an insurance claim. The exact result depends on your jurisdiction, so ask.
What to do first
Call the building department and ask how they handle a deck built without a permit. Many offices have a process for it. Bring photos of the framing, footings and ledger if you have them, because they cannot see inside a finished deck.
From Application to Final Inspection
The flow is similar everywhere, even where the forms differ. Know the stages before you pay a fee.
Before you apply
Check the setbacks, ask your HOA and read the department’s deck page. Decide whether your deck is attached, how high it sits and which footing depth your frost line requires. Our deck footing calculator sizes footings for common loads.
Review and inspections
You submit the application and drawings, pay the fee and wait for review. A reviewer may send the set back with comments, which is common when sizes are missing or the notes contradict the plan. After approval, inspections usually happen at footings, framing and final, and the department tells you which ones. Do not pour or cover anything before the inspector has seen it.
After the final
Keep the approved set and the inspection record. They are the proof the deck was built to code, and the next buyer’s inspector may ask for them. For decks that fall outside the prescriptive tables, such as a hot tub deck, an engineer’s design may be needed. Start with the deck span tables to see if your plan fits, then read deck drawings for permit.
If you are not sure your deck needs a permit, ask your building department first. This guide covers the rule and your local obligations. It does not replace their answer.
Sources
Every number in this guide that does not come from our own deck designer was checked against these 2 documents, numbered in the order the text first cites them and read between Oct 25, 2026 and Nov 4, 2026. 2 are code guides and official pages.
- 1Grant County, WashingtonExempt R105.2 (2021 International Residential Code, section R105) (2021)
- 2American Wood CouncilPrescriptive Residential Wood Deck Construction Guide (DCA 6, 2015 IRC version) (2015)
