If your deck is visibly pulling away from the house, the ledger connection — the board that ties the deck to the structure and carries roughly half its weight — is failing. This is the number-one cause of catastrophic deck collapse. It's fixable, usually for $800–$2,500, but it needs an inspection now, not after winter.
That's not fearmongering; it's just what the failure statistics say. When decks come down, they overwhelmingly come down at the house — the ledger lets go, the deck hinges away, and everything on it goes with it. The good news is that ledger failure is slow, visible, and very repairable if you catch it at the gap stage. Which, if you're reading this, you may have.
Why does a deck pull away from the house?
Three causes, and most failing ledgers have at least two of them:
- Nailed-only ledgers. Plenty of older decks were attached with nails instead of structural screws or bolts. Nails hold fine in shear — until decades of load cycles and seasonal wood movement slowly withdraw them. A nailed ledger doesn't fail suddenly; it backs away a millimeter at a time.
- Missing or failed flashing → rot. Flashing is the metal barrier that keeps water from running down the wall and behind the ledger. Without it, water sits in exactly the joint you can't see, rotting the ledger and the house rim the fasteners grip. A perfectly bolted connection into rotted wood is not a connection.
- Freeze-thaw working the fasteners. Colorado's winter cycles expand trapped moisture in every gap and thread. Each cycle loosens the hardware a fraction; every spring the deck hangs on a little less than the year before. This is why a gap you noticed in October is wider by April — and why waiting for spring is the wrong plan.
What should you check today?
Ten minutes, no tools beyond a screwdriver:
| Check | What you're looking for |
|---|---|
| The gap itself | Any visible daylight or widening seam where deck meets house — even a quarter inch matters |
| Rust streaks | Orange staining bleeding from the ledger or its fasteners; rusting hardware is losing section |
| Soft wood | Probe the ledger and the trim above it with a screwdriver — sound wood resists, rot gives |
| Flashing | Look for metal lapping over the ledger's top edge; no visible flashing is a finding in itself |
| Movement | Gentle rocking at the house side of the deck — any movement at the ledger is a stop sign |
And what not to do: don't load the deck while you wait. No parties, no hot-tub refills, no thirty-person barbecue. Ledger failures go from gap to collapse under crowd load — that's the recurring pattern in every collapse report. A deck that's separating can likely hold you walking across it; don't ask it for more than that. Our full inspection guide covers the rest of the structure while you're down there.
How is it fixed, and what does it cost?
The repair depends on what the inspection finds behind the ledger:
- Re-fastening — if the wood is sound and the attachment is the problem, the fix is structural lag screws or through-bolts on a proper schedule, replacing whatever nails were doing. The cheapest outcome, and common on decks caught early.
- Re-flashing — new flashing integrated with the housewrap so water never reaches the joint again. Almost always done alongside re-fastening, since the deck boards near the house come up either way.
- Ledger replacement — where rot has claimed the board, the ledger is cut out and replaced, along with any damaged rim framing behind it. All-in, ledger repair and re-flash runs $800–$2,500 in the Denver metro.
- Conversion to freestanding — when the house rim can't reliably hold a ledger (rot, brick veneer, cantilevered floors), the honest fix is a new beam on posts and frost-depth footings at the house side, so the deck stands on its own. It costs more than a re-fasten, but it removes the failure mode entirely.
If the inspection turns up rot beyond the ledger — joists, beams, posts — you're in repair-versus-replacement territory, and the math is covered honestly in our replacement cost guide. One silver lining: a properly repaired ledger is also step one of any future re-deck or rebuild, so the money isn't wasted either way. And this is exactly the class of repair worth doing before freeze-thaw season compounds it — see our repair service page for how we handle structural work.
Don't guess on this one
A separating ledger is the one deck problem where "keep an eye on it" is the wrong advice — severity is invisible from the surface, and the downside is the whole deck. Schedule a free structural inspection and we'll open it up properly: fasteners, flashing, rot probing, the works. You'll get a written verdict the same visit — re-fasten, replace, or convert to freestanding — with a real number attached, so you can fix it this fall instead of worrying about it all winter.
