Seattle Deck Permit Guide

Seattle has clear deck triggers based on height, roof-deck status, and environmentally critical areas.

Permit takeaway

Seattle says a deck needs a permit if it is more than 18 inches above ground, is a roof deck, or is in an environmentally critical area.

Zoning and placement

Environmentally critical areas can change what looks like a simple deck project into a more detailed permit review.

Building and trade review

Seattle notes that higher decks, long beams, roof decks, and ECA locations may require an addition or alteration construction permit rather than only field inspection.

Call before applying when

Call before applying if the deck is high above grade, on a roof, near a slope or flood-prone area, or uses long beams.

Documents to prepare

• Site plan
• Deck height above grade
• Framing plan
• Beam and footing details
• ECA information if applicable

Inspection planning

• Footing inspection if required
• Framing inspection
• Final inspection
• Additional review for ECA or roof deck conditions

Official sources

• Seattle Decks

This guide is a planning summary. Always verify the current requirements with the local office before starting work.