Repair or Replace Your Seattle Deck? What Each Costs

Repairs cluster in the low thousands. Replacements start near $7,000 and run to $30,000 in Washington. The published figures:

• Repair. A Seattle deck company puts the local average at $3,248, with a typical range of $1,276–$5,231. A Seattle and Bellevue builder gives roughly $1,300–$5,200 for a full deck repair.
• Small fixes. $50–$150 per decking board installed, $80–$200 for a stair tread, and $300–$600 to re-secure a wobbly railing.
• Re-decking a sound frame. $55–$75 per square foot, against $70–$95 for a new composite deck from the same Snohomish County builder.
• Full replacement. $7,000 to $30,000 for most Washington homes, plus $3–$8 per square foot to tear the old deck out.

Those are published ranges, not quotes. How we compile them explains the method and the price updates log records every change. Per-square-foot pricing for a new deck is in the deck cost guide.

At roughly 40 percent. The rule a Seattle deck company says local contractors work to is this: once the repair cost approaches 40 percent of the replacement cost, you replace. The reasoning is not sentimental. At that ratio you are buying an uncertain extension on an old frame instead of a new structure.

The same firm's figure for rebuilding a frame with rot in multiple posts, joist ends or the main beam is 60 to 80 percent of full replacement, which is well past the line. So the decision almost always turns on one question: is the damage in the surface or in the structure? Deck rot and structural repair covers how that gets established and what each framing member costs to put right.

When the frame is sound and the damage sits on top of it. A Seattle deck company's worked example: a 300 square foot deck with a quarter of its boards failed but a solid frame underneath prices out at $2,000–$5,000 in repair work, against tens of thousands to replace it.

Resurfacing is the middle path for a deck like that. New boards on an existing sound frame run $15–$40 per square foot from a Seattle builder, or $55–$75 per square foot from a Snohomish County firm whose figure takes in the railings. Either way you keep the footings, posts, beams and joists you already paid for. Compare the finishes in composite decks and cedar and pressure-treated decks before the boards are ordered, and read what deck repair and replacement says about having the frame checked first.

When the ledger is involved, when several framing members are gone, or when you are fixing something on it every year. Add the cost most homeowners do not see coming: once a deck project triggers a building permit, and structural repairs almost always do, current building code applies to the whole structure rather than only the part being repaired. On a deck built to an older code that can mean guardrail and stair work nobody budgeted for.

Seattle's current requirements give you a sense of what gets looked at. Guardrails are required on a deck more than 30 inches above adjacent surfaces, at least 36 inches tall, with openings no more than 4 inches in diameter, and stairs with four or more risers need a handrail. Railing work on its own runs $500–$4,000, or $25–$100 per linear foot. Read which repairs need a permit, city by city before you commit, because Bellevue and Edmonds both require one for a repair.

Both numbers, in writing, from the same visit. A useful assessment prices the repair completely, including the structural work and any code compliance it drags in, then prices full replacement next to it. Anything less and you are choosing between a real quote and a guess.

Ask for four things:

• A member-by-member list of what is compromised, from probing rather than looking
• The repair priced in full, with the permit and any code work included
• Replacement priced for the material you would actually choose
• The tear-out quoted as its own line, at $3–$8 per square foot

Check the company's registration on the state's L&I Verify tool first; the hiring checklist shows what that lookup tells you, and how we vet our deck pros covers the same check on our side. Then send your deck's details and our vetted local deck pro arranges the visit.