Deck Replacement in Kent, WA
Tearing out a deck that has reached the end and building the one that should have been there: what it costs, what the demolition uncovers, and why the new frame usually needs its own permit.
What Replacing a Deck Costs in Kent
The deck that came with a 1980s or 1990s Kent house is now thirty to forty winters old, and a lot of them are being priced for replacement this year.
Replacing a deck in the Kent area costs about $40 to $80 per square foot including tear-out and disposal, or roughly $8,000 to $25,000 for a typical 200 to 320 square foot deck. Replace rather than repair once rot has reached the joists, the ledger, or the posts.
The range is wide because the old deck decides part of it. Demolition and hauling run about $5 to $15 per square foot on their own, more when the deck is high, the access is a side gate, or the old frame was screwed together with hardware that has to be cut. The house wall behind the old ledger sometimes needs repair before the new ledger can go on. And a replacement is rarely a like-for-like rebuild: owners use the moment to go a little bigger, switch to composite, or add a roof, each of which moves the number.
Repair or Replace
A regional builder's rule is that a repair bill over half the cost of replacement means replace, and it is a good one, but the decision usually turns on where the rot is rather than what it costs.
- Replace when the ledger is soft, when two or more joists take a screwdriver, when posts have rotted at the base, or when the whole frame is undersized for the span it carries. The original 1980s deck was often built with joists on 24-inch centers and posts buried in the ground, neither of which passes today.
- Resurface when the frame is sound but the boards are done. New decking and rail on an old frame is the middle option and costs about $20 to $50 per square foot. It only works if a builder has crawled under and confirmed the joists are solid, dry, and spaced closely enough for the new boards; composite needs 16-inch centers or less.
- Repair when the damage is one place: a few boards, one stair stringer, a loose guard post.
The tell in Kent is the house wall. If the siding above the deck is stained or soft, or the floor inside near the door feels spongy, water has been getting behind the ledger for years, and the deck is the smaller of the two problems. Pull it, fix the wall, and rebuild.
What the Tear-Out Usually Finds
No flashing, or flashing that stops short
The most common discovery behind an old Kent ledger is a strip of bare rim joist that has been wet every winter since the house was built. The fix is a new rim section, house wrap lapped correctly, and a flashing that goes up behind the siding and over the new ledger, with the lateral hold-downs the state code now requires on attached decks.
Posts in the dirt
Older decks often stand on posts set directly in a hole with concrete poured around them. On East Hill, where a perched water table sits above the hardpan from December to April, the bottom of that post has been underwater for a third of every year. The replacement puts a footing below it and a metal standoff base between the concrete and the wood.
Stairs on a paver
Stringers resting on a concrete paver or on grade wick water up the end grain and are usually the first framing to go. New stairs get their own footing and a bracket that keeps the wood off the ground.