Roof Decking Types and Repairs
Decking, also called sheathing, is the layer of wood the underlayment and shingles are fastened to. HomeGuide gives it 20 to 40 years, depending on climate, ventilation and roof type. Nobody sees it until the old roof comes off, which is why decking is the line on a reroof quote most likely to change.
Plywood vs. OSB Sheathing
The residential code accepts any wood structural panel made to DOC PS 1 or PS 2 and stamped with its grade, which covers both plywood and oriented strand board (R803.2.1). HomeGuide's material prices:
- Plywood: $16 to $64 a sheet, or $0.50 to $2.00 a square foot.
- OSB: $9 to $60 a sheet, or $0.30 to $1.80 a square foot.
- Radiant barrier: some OSB comes with a foil face, and HomeGuide puts radiant barrier material at $0.10 to $0.60 a square foot.
Board (Plank) Decks on Older Homes
Some older houses have decks of sawn lumber boards instead of panels. The code sets lumber sheathing at a 5/8-inch net minimum over rafters 24 inches apart (Table R803.1). At reroof, boards up to 12 inches wide count as attached when they have two 8d nails at every rafter they cross, and nails are added where there are fewer (R908.7.1.1). Shingles and tile both need solid sheathing (R905.2.1, R905.3.1), so gapped boards get sheathed over or replaced.
Spot Sheet Replacement vs. Full Re-Deck
Spot replacement swaps out the sheets that are soft, usually along a leaking valley, a failed boot or an eave under an overflowing gutter. A full re-deck makes sense when rot is widespread or the old panels are too thin for the new covering. HomeGuide's numbers:
- Spot: $200 to $500 per 100 square feet.
- Labor: $1.50 to $3.00 a square foot, or $45 to $75 an hour.
- Full re-deck by roof size: 1,500 sq ft $3,000 to $7,500; 2,000 sq ft $4,000 to $10,000; 2,500 sq ft $5,000 to $12,500.
Where the decking is undamaged, HomeGuide notes, contractors may suggest leaving it alone.
Re-Nailing Schedule Under the Current Florida Building Code
Houses first permitted before the Florida Building Code get their deck re-nailed whenever the covering is torn off and replaced. That's R908.7 in the 2023 Florida Residential Code, 8th edition; homes permitted under the FBC are exempt. Existing 8d nails count only if they're at least 0.113 inch thick and 2-1/4 inches long. Table R908.7.1.2 then sets what gets added:
- Staples or 6d nails, any spacing: supplemental nails at 6 inches on center or closer.
- 8d nails at 6 inches or closer: nothing added.
- 8d nails farther apart than 6 inches: fill in to 6 inches on center.
The added nails must be ASTM F1667 RSRS-01 ring-shanks: 0.113-inch shank, 2-1/4 inches long, 0.280-inch round head. A closed-cell urethane adhesive tested to 200 psf is the code's alternative. The City (inspection code 115) and Leon County (also 115) check the re-nailing before underlayment goes on. The insurance credit it can earn is on the wind mitigation roof upgrades page.
Soft Spots, Rot and Sagging
HomeGuide's signs of rotted decking:
- spongy or flaking wood
- repeat leaks
- dark stains or mold on the attic side
- a mildew smell
- a sag in the roofline or ceiling
Moisture gets there through failed flashing, worn shingles, blocked gutters or a damp attic. Citizens' roof inspection form has its own box for "soft spots in decking", so an insurer will hear about it. Sagging can mean the rafters are damaged too, and HomeGuide prices rafter replacement at $5 to $14 a square foot.
Why Tallahassee homeowners call Tallahassee Expert Roofing
- Your request reaches one roofer, never a call list
- Homeowners pay nothing to use this line
- Ask for the shingle wind class and Product Approval number in writing
- The roofer's estimate is free and you're not obliged to hire
What the Decking Line in a Reroof Quote Should Say
The decking number is the part of a reroof quote that can grow after tear-off. Ask for these items before you sign:
Allowance
The number of sheets or square feet included, and a fixed price for each extra sheet.Material and thickness
Plywood or OSB, and the thickness, which must meet the code minimum for your wind speed.Nailing
Whether R908.7 re-nailing applies to your house, and dated photos of it. Leon County's reroof affidavit already asks for photos of every roof plane.Insurance
HomeGuide warns that some policies don't pay for code upgrades, such as thicker decking than the old roof had. Check before you count on the claim covering it.
Tear-off pricing, permits and timelines for the whole job are on the roof replacement page.