A building permit is required for the construction of a deck or platform when it is more than 30 inches from grade at any point. If the deck or platform is less than 30 inches but there is a roof, trellis or hot tub included in the project a permit is still required.
Suggestion: If you ever anticipate enclosing the deck as a screened-in porch, 3-season porch or enclosing as an addition or if you plan to add a trellis or hot tub, you will want to design the deck and footings for the increased loads and apply for a permit so that documentation is available for your footings and construction designs.
Examples of decks requiring permits:
For more information: