State Guide · Verified 2026
Deck Construction Permits in Minnesota
The only exception is a small freestanding platform 200 sq ft or smaller and no more than 30 inches above grade that is not attached to the house (IRC R105.2); any attached or elevated deck needs a permit.
The Building Code in Minnesota
Minnesota State Building Code, 2020 Minnesota Residential Code (2018 IRC based), Minnesota Rules 1300.0120
The Minnesota Dept. of Labor and Industry (DLI) administers the Minnesota State Building Code, which supersedes all local building codes; local governments enforce it but cannot amend any portion, a genuine statewide uniformity most states in this research don't have. Minnesota Rules 1300.0120 defines when a deck permit is required: if the deck is attached to a building, more than 30 inches above grade, part of a required accessible route, or built with frost-depth footings. This last trigger is more expansive than most other states: a structure that would otherwise qualify as an exempt platform can still need a permit if it happens to be built with footings that reach frost depth, even if freestanding and under 30 inches. Frost-depth footings themselves must reach 42 inches in southern Minnesota counties and up to 60 inches or more in the north.
Quick Facts
Who Sets the Rules
A genuinely locked statewide code
Minnesota is one of only a handful of states where local governments cannot amend any part of the state building code at all, only enforce it, meaning the deck permit rule is identical whether the project is in Minneapolis or a small town in northern Minnesota.
A trigger most other states don't have: the footing itself
Minnesota Rules 1300.0120 requires a permit if a deck is built with frost-depth footings, regardless of attachment or height, a genuinely more expansive trigger than the simpler height-and-attachment tests most states use. A freestanding, low platform that a builder chooses to set on deep footings for durability can still need a permit under this specific rule.
Duluth's own platform-versus-deck framing shows the pattern clearly
Duluth defines a "platform" as not attached to a building, not more than 30 inches above grade, and without frost-depth footings, exempt from a permit. Anything that fails any one of those three tests becomes a "deck" requiring a full permit and inspection process.
An extreme frost depth range within one state
Minnesota requires footings to reach 42 inches in southern counties and up to 60 inches or more in the north, among the deepest requirements in the country, reflecting the state's genuinely long, cold winters.
Even minor work can trigger a permit on cost alone
Under St. Paul's local code, a minor alteration that doesn't constitute normal maintenance still requires a permit if the labor and material value exceeds $500, a real, specific dollar threshold layered on top of the state's general deck rules.
What people get wrong
The most common mistake is assuming a low, unattached deck automatically qualifies as an exempt platform. If it's built with frost-depth footings, a common choice for long-term durability, it can still require a permit under Minnesota's specific rule, regardless of height or attachment status.
Counties With Their Own Rules
These Minnesota counties have verified, county-specific deck construction rules that differ from the state baseline:
Check Your County
Select your county for the local rule, fees, and your building department's contact details:
Building It Yourself? Here's What You'll Need
Popular tools and materials homeowners use for a deck construction project:
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Official Sources
Rules change and cities within a county may differ. This guide is general information, not legal advice — always confirm with your local building department. Reviewed by the StateDataIndex Editorial Team · Updated September 2026.