Permit or Not

Do I need a permit to build a deck?

It depends on the specifics

A permit is usually required once a deck is more than 200 square feet, more than 30 inches above grade, serves an exit door, or is attached to the house.

What changes the answer

These thresholds come from the model code and are commonly amended locally, which is usually where people get caught.

Why it matters

Deck collapses are among the most common structural failures in US homes, and almost all of them are ledger or footing failures. This is also the item most likely to be caught at resale.

Confirm the requirement with the authority that would issue the permit before deciding.

Why floating decks are treated differently

Almost everything about deck permitting comes back to one question: is this structure attached to your house? A ledger board bolted to the rim joist makes the deck part of the dwelling's structural system. It transfers load into the house, it penetrates the weather barrier, and when it fails it takes people down with it. Ledger failure — not rot, not undersized joists — is the leading cause of deck collapse in the US, and it is why that connection gets specific attention in the code and from inspectors.

A freestanding or floating deck carries its own load to its own footings. Nothing transfers into the house and nothing penetrates the cladding. That is the actual engineering reason it is treated more leniently, and it is why a floating deck under the size and height ceilings falls inside the IRC R105.2 exemption in most jurisdictions.

Worth being precise about hardware, because it is commonly misunderstood: hurricane ties and uplift connectors do not exempt you from anything. They are a construction requirement for resisting wind uplift, and where they are mandatory the jurisdiction is usually a high-wind area that has amended the code to be stricter, not looser. Building it properly tied down is how you make a deck that lasts and passes inspection. It is not what makes it exempt. The exemption comes from being freestanding, under roughly 200 square feet, under 30 inches at its highest point, and not serving a required exit door.

Height matters for two separate reasons that people conflate. Above 30 inches you generally need guards, which is a life-safety requirement. Independently, deeper footings and lateral bracing start to matter structurally as a deck gets taller, because the same wind and live loads act through a longer lever arm.

What catches people

This explains the typical rule and is not a decision about your property; confirm with your local building department before you start.

The version of this people actually ask

Do I need a permit to extend an existing deck?

An extension is new construction, and it is measured as the finished deck rather than as the piece you are adding. A 150 square foot deck plus a 100 square foot extension is a 250 square foot deck, which is over the usual ceiling even though neither number is on its own. The extension also normally has to tie into the existing frame, and that connection is structural work the inspector will want to see. Whether your jurisdiction reads it that way is worth confirming before you order lumber.

Do I need a permit to replace deck boards?

Replacing decking on a sound existing frame is usually treated as ordinary repair and commonly needs nothing. The line is the structure underneath: once you are replacing joists, beams, posts, footings or the ledger, you are past repair and into work that is typically permitted. Rot found mid-job is the usual way a board replacement turns into a structural one, so it is worth knowing where that line sits before you open it up.

Do I need a permit for a floating deck under 200 square feet?

This is the case the IRC exemption was written for, and it is the most likely of any deck to need nothing — provided all four conditions hold at once: not attached to the dwelling, not over 200 square feet, no point more than 30 inches above grade, and not serving the exit door the code requires. Three out of four is not the exemption. Setbacks still apply either way, because those are zoning rather than building code.

Do I need a permit to build a roof or pergola over my deck?

Nearly always yes, and independently of the deck below it. A cover is a roof structure: it carries snow and wind load, and where it attaches to the house it becomes part of the dwelling. People get the deck exemption right and then add a cover on the assumption it rides along with it. It does not.

Do I need a permit to stain or resurface my deck?

Staining, sealing and cleaning are maintenance and are not permit items anywhere we know of. Resurfacing gets a caveat worth naming: composite decking is heavier than the wood it usually replaces, and adding weight to a frame designed for something lighter is a structural question even where nobody asks you to file anything.

This is the typical rule, not your answer

This is the typical rule in the United States and not a decision about your property — permitting is run by more than 22,000 separate authorities and any of them can amend the code it adopts, so confirm with your local building department before you start. Put a ZIP in to see what applies in that state, and how to reach the office that decides.

IRC R105.2 exemption for decks not exceeding 200 sq ft, plus R507 for deck construction.

Build a deck state by state

Which building code a state adopts, and whether it binds the whole state or leaves it to each city, changes how far the rule above gets you. These pages carry that, plus the county building departments we have verified in each.

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