Roof Decking Replacement Cost in 2026

Low$500

a few soft sheets around a chimney or a leaking valley — roughly 6 sheets, or 2 squares of deck

Typical$2,000

scattered replacement across a roof that has been leaking slowly for years — around 15 sheets, or 5 squares

High$14,000

a full re-deck, typically an older home with plank sheathing being covered or replaced for a modern roof assembly

A long-running leak

Water spreads along the deck and down the rafters. A single failed boot that has leaked for three winters can rot a surprising area around and below the penetration.

Plank or board sheathing

Older homes often have spaced 1x boards rather than panels. Modern shingles need a solid deck, so the fix is usually to overlay the whole roof in plywood — a re-deck, not a patch.

Thicker panels required by rafter spacing

Wide rafter spacing needs 5/8" rather than 7/16", and the price steps up with the thickness.

Steep pitch and height

Handling 4x8 sheets on a steep roof two storeys up is slow, awkward work with a real safety cost built into it.

Ice-dam damage at the eaves

In cold climates the deck failure is concentrated in the first few feet above the wall, which is also the hardest place to work and the place where new ice-and-water membrane has to be integrated.

Catching leaks early

Decking damage is cumulative and almost entirely preventable. The homeowner who fixes a boot the first winter never sees this line item.

Doing it during the re-roof

Replacing sheathing with the roof already open costs a fraction of what it costs as a separate job, because the access is already paid for.

Negotiating the rate before the tear-off

Not a discount exactly, but the difference between a known cost and an unknown one — which in practice is where the money is.

How much decking usually needs replacing?

On a roof that has not leaked, often none or a sheet or two. On a roof with known leaks, a handful of sheets around each problem area. On an old roof that has leaked for years, it can be a large share of the deck. Nobody can tell you which case you are in from the ground, and a contractor who confidently promises "no decking" before tear-off is guessing.

Can the contractor just decide to replace the whole deck?

They should not, and your contract should say so. A reasonable clause requires photographs of the damaged area and your approval above a set threshold — for example, anything over five sheets. That protects both sides and costs nothing to include.

OSB or plywood?

Both are code-compliant and both are fine when they stay dry. Plywood tolerates a wetting event better and dries out rather than swelling permanently at the edges; OSB is cheaper and more common on new construction. On a small patch, matching the existing thickness matters more than the material choice.

Does insurance cover decking replacement?

Only where the decking was damaged by a covered event — impact from a limb or hail, or water intrusion from a covered storm. Sheathing that rotted slowly from an old leak is a maintenance issue, and every standard policy excludes it.