Weekend deck off the patio door
The homeowner and two friends built this 12 x 16 ft deck over two weekends in a city that enforces the State Building Code. The ledger bolting, flashing and footings were all done to code. Nobody applied for a permit because 'it's just a deck.' What's the problem?
- A deck attached to the house and more than 30 in. above grade needs a building permit, and this one was built without one
- Decks of 200 sq. ft. or less never need a permit, so this 192 sq. ft. deck is exempt
- A homeowner can build a deck without a permit; permits are only for contractors
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
The deck is attached to the house and stands about 8 ft above grade, so it needed a building permit that was never applied for.
Correct choice: 1. A deck attached to the house and more than 30 in. above grade needs a building permit, and this one was built without one
In Minnesota the State Building Code's administrative chapter, not IRC chapter 1, decides when a permit is needed. Minn. Rules 1300.0120, subp. 1 requires the owner or authorized agent to get a permit before constructing a structure regulated by the code. Subpart 4 exempts decks and platforms only when they are not more than 30 in. above adjacent grade, not attached to a structure with frost footings, and not part of an accessible route. This deck fails the first two tests: it is bolted to the house and stands about 8 ft above the lawn. A deck this high is a fall hazard, and the footing, ledger, and framing inspections are how the city confirms it will hold a crowd. Even an exempt deck has to meet the code.
How to fix it
Apply for a building permit now. Expect to submit a deck plan and to open up or demonstrate work the inspector cannot see, such as footing depth and ledger fastening, possibly with an extra fee for work started without a permit. Correct anything the inspector finds before the deck is used.
Code references
Minn. Rules 1300.0120, subp. 4 — Permits: work exempt from permit
Exempt from a building permit: decks and platforms not more than 30 inches above adjacent grade, not attached to a structure with frost footings, and not part of an accessible route (along with other listed items). An exemption does not authorize work that violates the code or other laws or ordinances.
Drills citing 1300.0120, subp. 4Minn. Rules 1300.0120, subp. 1 — Permits: required
An owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or cause that work to be done, must first apply to the building official and get the required permit.
Drills citing 1300.0120, subp. 1IRC 2018 R105.2 — Work exempt from permit (model code)
The model IRC exempts decks not over 200 sq. ft., not more than 30 in. above grade at any point, not attached to a dwelling, and not serving the required exit door. Minnesota does not adopt IRC chapter 1; Minn. Rules 1300.0120 governs permit exemptions instead.
Drills citing R105.2
Minnesota
This drill tests State Building Code administration (Minn. Rules ch. 1300), which replaces IRC chapter 1 in Minnesota. The Minnesota Residential Code (Minn. Rules ch. 1309) adopts the 2018 IRC with Minnesota amendments for how the deck is built. DLI has begun rulemaking toward the 2024 IRC (no effective date yet), and chapter 1300 may change with it. Where a city does not enforce the State Building Code, no building permit may be issued at all, but the code still applies (Minn. Stat. 326B.121).
About the Minnesota Residential CodeCitation under review. Audited 2026-10-04. The 1300.0120 subp. 4 deck wording ('not more than 30 inches above adjacent grade and not attached to a structure with frost footings and which is not part of an accessible route') was re-confirmed through search results quoting the rule and city deck handouts (direct fetch blocked). No search result showed an area limit on the Minnesota deck exemption. IRC 2018 R105.2 item 10 (200 sq. ft., 30 in., not attached, not serving the required exit door) is from memory of the model code and was not re-checked by search.
Why the other choices are wrong
- Decks of 200 sq. ft. or less never need a permit, so this 192 sq. ft. deck is exempt. The 200 sq. ft. figure comes from the model IRC (R105.2), and even there it applies only to low, detached decks. Minnesota's exemption (Minn. Rules 1300.0120, subp. 4) covers only decks and platforms 30 in. or less above grade that are not attached to a structure with frost footings.
- A homeowner can build a deck without a permit; permits are only for contractors. Minn. Rules 1300.0120, subp. 1 puts the permit duty on the owner or authorized agent. Doing the work yourself does not remove the permit requirement.
- Nothing. This installation is compliant. The deck is attached to the house and sits about 8 ft above grade. That takes it out of the permit exemption, so a building permit and its inspections were required.