https://www.seattle.gov/sdci/permits/common-projects/decks
You need a permit to build a deck if it is:
- More than 18 inches above the ground
- A roof deck (built on top of part of the building)
- In an environmentally critical area (ECA), for example landslide-prone areas
You probably need an addition or alteration construction permit if your deck meets any of these criteria:
- It will be more than 8 feet above the ground
- It includes long beams
- It will be a roof deck
- It will be located in an environmentally critical area
