Roof Decking Replacement Cost: Per Sheet and Per Square Foot

Replacing roof decking during a re-roof typically costs a few dollars per square foot, or roughly $70 to $100 per sheet. Fixr reports $2 to $8 per square foot for replacing roof decking (page updated February 4, 2026) ¹. Modernize says to expect $70 to $100 for each sheet of plywood, depending on the roofer's labor rate (updated September 2, 2026) ². A standard sheet is 4 by 8 feet and covers about 32 square feet of roof ².

How much decking a roof needs is the one number nobody knows until the old roof is off. That is why decking is often priced per sheet in the contract and billed after tear-off, and why it can make a roof's final bill differ from its quote. The sections below show the ranges, a worked example and how to keep the surprise small.

What roof decking is

Decking, also called sheathing, is the layer of wood panels nailed to the rafters or trusses; the underlayment and shingles go on top of it. APA, the engineered wood trade association, says its rated sheathing panels are made from either plywood or OSB (oriented strand board) ⁶. The panel's stamp carries a span rating such as 24/16; for roof use, the left-hand number is the maximum recommended spacing of the supports, in inches ⁷. Modernize says plywood sheathing runs from 1/4 inch to 5/8 inch thick ². The thickness and rating a roofer uses depend on the rafter spacing and local code, so ask which panel the quote assumes.

The sources here do not give separate installed prices for plywood and OSB, so we do not either. Ask each roofer which they use and what they charge per sheet for it.

Decking cost by source

By our arithmetic, Modernize's $70 to $100 per 32-square-foot sheet works out to about $2.19 to $3.13 per square foot ², inside the low end of Fixr's $2 to $8 range ¹. The Fixr repair, Modernize swap and This Old House figures are for standalone repair jobs, not decking replaced during a full re-roof.

A worked example

By our arithmetic, using Modernize's per-sheet range ²:

• A few soft spots, 10 sheets: 10 × $70 to $100 = $700 to $1,000 ².
• A quarter of a 2,000-square-foot roof, about 16 sheets: 500 ÷ 32 = 15.6, rounded up to 16; 16 × $70 to $100 = $1,120 to $1,600 ².
• The whole 2,000-square-foot roof, about 63 sheets: 2,000 ÷ 32 = 62.5, rounded up to 63; 63 × $70 to $100 = $4,410 to $6,300 ².

At Fixr's per-square-foot range, the whole 2,000-square-foot roof would be $4,000 to $16,000 ¹. Modernize says new decking could add several thousand dollars to a roofing project ².

Why decking shows up as a change order

Fixr says that once the old roof is removed, contractors may uncover hidden damage from long-term leaks ¹. Modernize says roof problems are not always obvious from the ground, and names rotten or soft decking as the leading problem uncovered during a tear-off ². A full replacement job of the kind the Cost vs. Value report prices strips the roof to bare wood sheathing ⁸, which is the moment every sheet can be seen and tested.

Because of that, a roofing quote usually cannot give a fixed decking total. What it can and should give is:

• A per-sheet price for any decking replaced, in writing, before work starts.
• A count rule: who decides a sheet is bad, and whether you see photos or the removed sheets before it is billed.
• An allowance, if any: if a quote includes some sheets in the base price, know the number and the price for each sheet beyond it.

A quote that says only "decking as needed" with no per-sheet price leaves the final number open. Compare quotes on the per-sheet price as well as the base price; how to compare roofing quotes covers the other lines to check.

Signs the decking may need work

A roof that sags, feels soft underfoot or has a history of leaks deserves a closer look, and the attic is where a roofer can see the underside of the deck. Whether damaged decking tips the decision from a repair to a full replacement is covered in repair or replace a roof and roof leak repair cost.

For the full price of a new roof, see the roof replacement cost guide, and for questions about the company itself, how to choose a roofing contractor. You can compare quotes from roofing companies and ask each for its per-sheet decking price.

About these figures

• ¹ Reported + Estimate: Fixr decking replacement range of $2 to $8 per square foot and the hidden-damage statement; page updated February 4, 2026, checked November 11, 2026. The $4,000 to $16,000 whole-roof figure is our multiplication of that range by 2,000 square feet.
• ² Reported + Estimate: Modernize per-sheet price ($70 to $100), sheet size and coverage, thickness range and the statements on where damage is found and its effect on the total; page updated September 2, 2026, checked November 11, 2026. The per-square-foot conversion and the sheet-count examples are our arithmetic from those inputs.
• ³ Reported: Fixr decking repair range ($150 to $1,000); page updated January 21, 2026, checked November 11, 2026.
• ⁴ Reported: Modernize decking swap per affected area ($700 to $2,500 or more); page updated October 12, 2026, checked November 11, 2026.
• ⁵ Reported: This Old House moderate repair range ($1,001 to $2,000), which includes repairing underlying felt or decking; page updated March 5, 2026, checked November 11, 2026.
• ⁶ Directional: APA statement that rated sheathing is produced from plywood or OSB; checked November 11, 2026.
• ⁷ Directional: APA explanation of the span rating on a panel stamp; checked November 11, 2026.
• ⁸ Reported: Cost vs. Value asphalt job scope (tear-off to bare wood sheathing); checked November 11, 2026.