Do I need a permit to build a deck? The answer is usually yes — and the exceptions are narrower than most people think. An attached deck or a raised deck needs a permit almost everywhere. A low freestanding deck often does not. The rule is local: your city or county decides, and the building department is the only source that counts. This guide covers the triggers, the exceptions, and what happens if you skip it.
An attached deck needs a permit. A raised deck needs a permit. A low freestanding deck — under 18 inches high, not attached to the house — often does not. The height, the attachment, and the size are the three triggers, and every city sets its own thresholds. Applying is the process itself — the building permit application guide covers how to file.
Three things trigger a permit: the deck attaches to the house, the deck is raised off the ground, or the deck is large. An attached deck loads the house wall — the ledger board connection is the most common deck failure, and the inspector checks it. A raised deck needs railings and footings, and the inspector checks those too. A large deck needs more of everything. The exact thresholds vary: one city draws the line at 18 inches, another at 30, and another at any height at all.
A low freestanding deck — a platform under 18 inches high, not attached to the house, and under the city's size limit — usually does not need a permit. It is a platform, not a structure: no ledger, no railings, no footings below the frost line. But "usually" is the word that matters: some cities require a permit for any deck, and some homeowners associations require approval even when the city does not. A roof has the same question — the roof replacement permit guide covers when a roof needs one.
| Deck type | Permit? | Why |
|---|---|---|
| Ground-level, freestanding, under 18 inches | Usually no | Platform, not a structure — no ledger, no railings |
| Attached to the house | Usually yes | Ledger board loads the house wall — the most common failure |
| Raised, over 30 inches | Yes | Railings and footings required, and the inspector checks them |
| Deck with a roof or pergola | Yes | Roof structure adds load and needs its own review |
| Replacing a deck, same footprint | Depends | Same size and height may not need one — ask first |
A stop-work order, a fine, and a deck you have to tear down or bring up to code — after it is built. The fine is usually a few hundred dollars, but the teardown is the expensive part. And the problem follows you: an unpermitted deck shows up in the seller's disclosure when you sell, and the buyer's inspector flags it. A shed has the same trap — the shed permit guide covers the rule that it depends on your city, not your opinion.
Usually yes — an attached deck or a raised deck needs a permit almost everywhere, while a low freestanding deck often does not. The rule is local: call your city or county building department before you buy lumber.
Usually $100–$500, depending on the city and the size of the deck. The fee is based on the project value, and most cities publish a fee schedule online.
One to four weeks for a straightforward deck, longer if the plans need corrections. Submit the plans early — the permit, not the lumber, is the long pole in the schedule.
A stop-work order, a fine, and a deck you may have to tear down or bring up to code. The problem follows you to the sale: an unpermitted deck shows up in the seller's disclosure and the buyer's inspector flags it.
Yes, if it needed a permit. The inspector checks the footings before the concrete is poured, the ledger board connection, and the railings — the three places decks fail.