Do I Need a Permit to Build a Deck?

In almost every US jurisdiction, the answer is yes. A deck is a structure people stand on, often several feet in the air, attached to the house — so building departments want to see it before and during construction.

When a permit is required

• Any deck attached to the house (because of the ledger connection).
• Any deck more than about 30" above grade.
• Most freestanding decks above a small size threshold set locally.

Some areas exempt small, low, ground-level platforms — but check, because the threshold varies and an unpermitted deck can derail a home sale.

What the inspector checks

• Footing depth and size (inspected open, before the pour).
• Ledger attachment and flashing — the #1 cause of deck collapses.
• Joist and beam sizes against the IRC R507 span tables.
• Post connections, guard height and stair dimensions.

Passing the first time

Submit a simple plan that names your joist size and spacing, beam size, post spacing, footing size and depth, and stair layout — exactly the outputs this calculator gives you. When your drawings cite the same R507 tables the examiner uses, approval is usually quick.