Deck Replacement Cost Calculator

Deck replacement typically runs $20 to $55 per square foot, so replacing a 300 sq ft deck is roughly $6,000 to $16,500. The biggest lever is how much you replace: re-decking just the surface over a sound frame is the cheapest, replacing the boards plus framing is mid-range, and a full tear-out and rebuild with new footings is the most expensive. The new material (pressure-treated up to PVC) and the deck's height also adjust it, and the price includes demolishing and hauling away the old deck.

It hinges entirely on the substructure. If the joists, beams, posts, footings, and the critical ledger connection are sound and up to code, re-decking — new boards and railing over the existing frame — saves a lot of money and time. But covering a deteriorating frame with nice new boards is dangerous, since deck collapses almost always come from structural or connection failures, not the boards. If the framing is rotted, undersized, or the ledger is compromised, a full replacement gives you a safe, code-compliant structure. A frame inspection is the deciding step.

Look for structural warning signs: soft, spongy wood that a screwdriver sinks into (probe the joists, posts, ledger, and stair stringers); a deck that sways or feels unstable; rusted or missing fasteners and joist hangers; a ledger attached with just nails and no flashing; widespread cracking or cupping of boards; and heaved or cracked footings. Age matters too — wood decks generally last 15 to 25 years, and one built before current codes may be unsafe even if it looks fine. Isolated damage means repair; widespread, structural, or connection problems mean replacement.

Often yes — that's the basis of the economical re-deck approach — but only after a careful inspection. The joists and beams must be free of rot and cracks and properly sized and spaced (note some composites need closer 12-to-16-inch joist spacing than older decks have, which may require adding joists). The ledger must be properly bolted and flashed, and posts and footings must be solid and anchored, not heaved or buried in soil. Even when reusing the frame, contractors often add protective joist flashing tape over the old joists to extend their life and may upgrade connections to meet current code.

Replacement is the natural time to upgrade. Pressure-treated is cheapest but needs regular staining and lasts 15 to 20 years. Cedar and redwood look better and resist rot naturally but still need sealing. Composite (like Trex) costs more upfront but is low-maintenance — no staining — and lasts 25 to 30-plus years with long warranties. PVC is the priciest and most durable, fully resistant to moisture, rot, and insects. Since you're already paying for demolition and labor, upgrading to a longer-lasting material is often the smart move if you're keeping the home a while.

The ledger board bolts the deck to your house and carries a large share of its load — and improper ledger attachment is a leading cause of deck collapses. A replacement is your chance to get it right: fastened with proper lag bolts or structural screws (not nails), flashed to keep water out of the home's rim joist, and inspected. Many older decks have a nailed, unflashed ledger, which is exactly the kind of defect a full or partial replacement corrects. If you're reusing the frame, the ledger still gets verified and re-flashed as needed.

Usually for structural work, yes. Simply swapping the surface boards on an unchanged structure often doesn't need a permit (though some areas still want one). But replacing framing, footings, or the ledger, changing the deck's size or height, rebuilding stairs, or a full tear-out and rebuild almost always requires a permit and inspection. Importantly, even if your old deck was unpermitted or built to an older code, the replacement must usually be brought up to current code — which the permit process enforces. Skipping a required permit risks fines, insurance issues, and resale problems.

Joist flashing tape is a self-adhesive membrane applied along the top edge of the joists before new boards go down. It stops water that collects between the deck boards and the framing from soaking into the joist tops — the exact spot where reused wood frames start to rot. On a replacement where you're keeping the existing frame, it's cheap insurance (about $1/sq ft) that meaningfully extends the substructure's life. It's especially worth it when re-decking over an older frame you want to get many more years out of. The calculator includes it as an add-on.

A new build adds a deck where none existed — design, permitting, footings, framing, and surface on a clean site, no demolition. A repair fixes isolated problems on an otherwise-sound deck: a few boards, a loose rail, a joist hanger. Replacement removes an existing deck, in whole or part, and builds new in its place — from re-decking the surface over a sound frame to a full tear-out — and always includes demolishing and disposing of the old deck. Cost rises along that ladder: repair, re-deck, partial replacement, full rebuild, new build.

It ranges from a few days to about two weeks. A surface re-deck on a sound frame is fastest — often a few days, since there's no structural or footing work. Replacing the framing adds time for tear-out and rebuilding. A full tear-out and rebuild takes longest, commonly one to two weeks, because it includes demolition, possibly new footings (concrete needs to set), the new substructure, and then decking, railing, and stairs, with inspections at key stages. Permitting before the start, inspection scheduling, deck height, and weather can all stretch the timeline.