Published August 28, 2026
Short answer: in most Minnesota cities, yes. The common threshold is a deck more than 30 inches above grade, attached to the house, or over 200 square feet — and many cities require a permit regardless of size once it is attached.
Requirements vary by city. Always confirm with your building department before digging.
What triggers a permit
- Attached to the structure (nearly always requires one)
- Walking surface more than 30 inches above grade
- Over 200 sq ft in many jurisdictions
- Any roof, pergola cover, or electrical
A freestanding, ground-level platform under those thresholds is often exempt — but setbacks and easements still apply.
The Minnesota-specific part: frost footings
Footings must bear below the frost line. In most of the metro that means 42 inches; northern counties go deeper. This is the single biggest difference between a deck built here and one built in a warmer state, and it is why a "cheap" deck bid that skips proper footings will heave, rack, and pull away from the ledger within a few seasons.
Inspectors verify footing diameter and depth before concrete goes in. That is a hard stop.
What inspectors check
- Footing inspection — open holes, correct depth and diameter.
- Framing inspection — ledger attachment and flashing, joist hangers, beam sizing and span, post-to-beam and post-to-footing connections.
- Final — guardrails 36" minimum residential height, balusters that block a 4" sphere, stair rise/run consistency, and a graspable handrail on stairs with four or more risers.
The ledger is where most failures originate. It must be through-bolted or lag-screwed to the rim joist per schedule and properly flashed. Nails alone do not pass.
Typical timeline and cost
Permit fees in the metro commonly run $150-$500 depending on valuation. Plan review is usually a few days to two weeks. Build in an extra week for the footing inspection window.
Why it matters beyond the fine
An unpermitted deck shows up at resale, can void a homeowners claim if someone is injured, and often has to be torn out and rebuilt for the buyer. Permitting is cheap compared to that.
We pull permits on every deck we build and schedule the inspections. If you already have a deck you are not sure about, we can assess the footings and ledger and tell you where it stands.
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Estimated project range
$6,900 – $13,500
Twin Cities 2026 pricing. A ballpark only — access, soil, permits, and condition move the real number. Send it over and we'll price your actual project for free.
Frequently asked questions
How deep do deck footings need to be in Minnesota?
Below the frost line, which is typically 42 inches in the Twin Cities metro and deeper in northern counties. Inspectors verify depth before concrete is poured.
Do I need a permit for a ground-level deck?
Often not, if it is freestanding, under 30 inches above grade, and below your city size threshold. Setbacks and easements still apply, so confirm with your building department.
What do deck inspectors look at?
Footing depth and diameter, ledger attachment and flashing, joist and beam connections, then guardrail height, baluster spacing, stair rise and run, and handrails at final.