Start by sorting the problem into two piles
Every deck issue falls into one of two categories: cosmetic or structural. Cosmetic problems are annoying but not dangerous - gray, weathered boards, a little surface splintering, a railing that's loose but not moving at the connection, gaps between deck boards. These get fixed with sanding, board swaps, screws, and stain. They don't threaten anyone's safety and they're the cheap end of the repair spectrum.
Structural problems are different. They involve the parts of the deck that carry weight and keep it attached to your house: the ledger board, the footings, the posts, the beam, and the joists. If any of those are compromised, you're no longer deciding between "fix it" and "leave it" - you're deciding between "fix it now" and "someone gets hurt."
The ledger board and footings: where repair turns into a dealbreaker
Two components decide more deck fates in this metro than anything else.
The ledger board
This is the board that bolts your deck directly to your house's rim joist. Minnesota code sets minimum sizing for this connection - a ledger attached to the exterior wall of the primary structure has to be at least 2-inch by 8-inch nominal lumber, with specific fastener and flashing requirements. In practice, the ledger is also the single most common failure point on older Twin Cities decks, because it sits where snowmelt, ice, and splash-back concentrate against the house. If flashing was missing or installed wrong when the deck went up (common on decks built before the mid-2000s), water has been getting behind that board for years. Soft, spongy, or delaminating wood at the ledger isn't a repair - it's a sign the connection to your house has been failing quietly.
The footings
Deck posts have to bear on concrete footings sized and placed to code, and freestanding decks under 30 inches high are the only ones exempt from extending footings below the frost depth. Everything else needs footings deep enough to stay below where the ground freezes. Minnesota's freeze-thaw cycle is hard on shallow or undersized footings - frost heave can lift a post out of alignment over a few winters, and once a footing has moved, patching around it doesn't fix the underlying geometry problem. A tilted post or a footing you can rock by hand means new footings, not a shim.
Here's the practical rule: if the problem is in the decking, railings, stairs treads, or fasteners, it's repairable. If the problem is in the ledger, the footings, or a rotted/cracked post or beam, get a contractor to actually open it up and look before you assume "repair" is even on the table.
Where the cost math flips from repair to replace
On this platform, a typical deck repair job in the Twin Cities runs $850-$2,200. That range covers things like replacing a section of rotted decking, swapping out a few joists, fixing a railing, or re-securing a ledger connection that's caught early. Where you land in that range depends mostly on square footage affected and whether the repair requires re-opening finished decking to get at framing underneath.
The crossover point comes when you're stacking multiple structural fixes on the same deck: a ledger reattachment, plus footing replacement, plus joist sistering, plus decking that's too far gone to keep. At that point you're paying labor to demo and rebuild most of the deck piece by piece - and a full teardown-and-rebuild often ends up cheaper per square foot than a patchwork of major structural repairs, because the contractor isn't working around what's still standing. As a rule of thumb: if a contractor's repair estimate is creeping toward the top of that $850-$2,200 range and still doesn't cover everything wrong with the deck, ask for a straight replacement quote before committing to the repair.
Age matters too. A deck built with untreated fasteners, no ledger flashing, or footings that don't meet current code is a deck where every future repair is a bandage on a design problem. If yours is 20+ years old and just failed its first structural inspection, replacement usually wins the math over time even if the immediate repair number looks smaller.
Safety-first cases: stop using the deck now, decide later
Some conditions mean you keep people off the deck immediately, before you've even figured out repair vs. replace:
- Any visible gap or separation between the ledger board and the house
- A post you can rock, twist, or that sits on a cracked or heaved footing
- Soft, spongy, or crumbling wood anywhere in the framing (not just decking)
- Guardrails that move when pushed, or top rails that flex noticeably
- Visible rust-through or missing fasteners on ledger bolts or joist hangers
- Any noticeable sag, bounce, or "give" in the deck surface underfoot
None of these need a formal inspection to act on - if you see them, restrict access and get someone qualified to look before the next gathering, not after.
Permits: don't assume you're exempt
In Minneapolis and St. Paul, deck permits aren't just for new builds. In St. Paul and most of the Minneapolis metro area, building permits are required for new deck construction and for most structural repairs or replacements - and touching the ledger board, sistering joists, or adding/relocating footings all typically trigger that requirement, even on an existing deck. Minneapolis goes further: deck projects require a permit even if you're tearing down an old deck and rebuilding one the exact same size. Small cosmetic work - replacing a few boards, repainting, tightening a railing - generally doesn't need one. If your contractor is proposing to touch the ledger or footings and doesn't mention a permit, ask why.
Get an exact number instead of guessing
Every deck's condition is specific to that deck - its age, ledger flashing history, footing depth, and how much framing is actually affected. The fastest way to get a real answer for yours: take a few photos of the problem areas (ledger connection, any post bases, the underside of the decking if you can get under it), describe what you're seeing and how old the deck is, and get an instant local price range built from what jobs like yours actually cost in the Twin Cities. That's a faster and more honest starting point than a generic "repair vs. replace" rule, because it's based on your deck, not an average one.