Deck Repair & Replacement in Portland, OR: Rot to Rebuilds

Last updated October 9, 2026

Deck repair in Portland: start with the frame

Portland decks do not usually fail all at once. A board goes soft near the house, a railing post starts to rock, moss turns the steps slick every winter. Whether the answer is deck repair or deck replacement depends less on the boards you can see than on the frame you cannot: the posts and footings, the beams and joists, and the ledger board that holds an attached deck against the house. On a sound frame, almost anything above it can be replaced. Once the frame itself is rotten or moving, patching the surface only hides the problem.

Tell us what you are seeing and a local deck contractor will look at it and give you a free quote, whether that turns out to be a few boards, a full re-deck or a new deck.

Signs your deck needs work

The North American Deck and Railing Association, which declared May Deck Safety Month, publishes a Check Your Deck consumer checklist. These items from it matter most on a Portland deck:

• Split or decaying wood. The checklist says that if you can easily penetrate the wood a quarter to half an inch, break off a sliver without splinters, or the wood is soft and spongy, decay may be present. Check boards, joists and posts where they stay wet: near the house, under planters and at the bottom of the stairs. Oregon State University Extension notes that wood which stays wet from rain decays faster, and Portland International Airport’s normal is 36.92 inches of rain a year (NOAA, 1991-2020).
• Flashing. The metal or membrane flashing over the ledger keeps water away from the house framing. Oregon’s statewide permit-ready deck plan requires ledgers to be flashed to prevent water from contacting the house band joist.
• Loose or corroded fasteners. Rusted nails, screws and connectors, and bolts that have worked loose at the ledger or the posts.
• Railings, banisters and stairs. Any give in a guard post or a handrail, and treads that flex or have rotted at the stringers.
• Moss. Oregon State University warns that moss on decks can be slippery. It names pressure washing as effective for decks and notes that after a moss killer the dead moss still has to be removed.

NADRA notes that its checklist is meant to help homeowners and that checking a deck this way does not make it code compliant. It is a reason to call someone, not a substitute for a contractor looking at the frame.

Is it cheaper to repair or replace a deck?

When the frame is sound, repair is the smaller job: the posts, beams and joists stay, and only what is damaged is replaced. Replacing the whole deck means demolition, new footings and framing, and a permit for any deck more than 30 inches above the ground, so it is the bigger job by some way. The one thing that should decide it is the frame. If a contractor recommends replacement, the quote should say what they found: rot in the joist ends, a ledger pulling away, posts sitting in wet soil. If they recommend repair, it should say the frame was checked.

Our page on what a deck costs gives the most recent published Portland figures for building a complete new deck, which is the useful number to compare a large repair against.

What can you put over an existing wood deck?

New boards. Re-decking keeps the existing frame and replaces the surface, either with wood again or with composite or PVC boards. Two things to know first. The frame has to be sound, because new boards on tired joists will not last any longer than the old ones did. And the code ties joist spacing to the decking material (2023 Oregon Residential Specialty Code, R507.6), so a frame built for thick wood boards may need joists added before composite can go on. Our comparison of the best decking for Portland’s climate covers the board choices.

When a deck repair needs a permit

Oregon’s permit exemption is about height, not about whether the deck is new: a deck whose walking surface is no more than 30 inches above the ground, measured within 3 feet, does not need a building permit under the Oregon Residential Specialty Code. Above that line, rebuilding counts. West Linn’s building division, for one, states that a permit is required “whether it is the re-construction of an existing deck, or if it is a brand new deck.” How each city treats smaller repairs varies, and a few, like Lake Oswego and Happy Valley, add engineering rules for tall decks. Our guide to deck permit rules sets out what Portland and the suburbs require, and the railings a repaired deck must have are in our guide to deck railing height and stair code.