Do I Need a Permit to Build a Deck in Wisconsin?

Decks are regulated under Wisconsin's Uniform Dwelling Code, and a building permit is required in most municipalities. The UDC applies to all attached and elevated decks, and any deck surface more than 30 inches above grade requires a permit statewide. Even ground-level decks may require permits in cities like Milwaukee and Madison, which require permits for all attached decks regardless of height. To get a deck permit, you will need to submit a site plan showing the deck's location relative to property lines (setback compliance), a construction plan detailing footing sizes, post-to-beam connections, joist sizing, ledger board attachment, and railing details. Footings must extend at least 48 inches below grade in most of Wisconsin to get below the frost line (42 inches in some southern counties). Deck permits typically cost $75 to $600 depending on the municipality and deck size. Plan review takes 1 to 3 weeks. Inspections typically include footing (before pouring concrete), framing, and a final inspection. Ground-level patios made from pavers or poured concrete at grade are generally exempt from building permits, though they may still need to comply with zoning setback requirements.

Check Your Municipality

Permit requirements, fees, and exemptions vary by municipality. Verify the specifics for your location.