What Is Roof Decking?
Roof decking (sheathing) is the plywood or oriented strand board fastened to the rafters that carries the underlayment and shingles. Most Austin-area homes built since the early 1980s use 7/16-inch to 5/8-inch OSB or plywood. Decking condition cannot be fully known until tear-off, which is why reputable contractors quote a per-sheet replacement price in the written estimate rather than surprising the homeowner mid-job; on a typical Central Texas re-roof, a small percentage of sheets commonly needs replacement. Soft spots, sagging between rafters, delamination, and moisture staining visible from the attic are the warning signs. Rotted decking discovered during an insurance replacement is a frequent legitimate supplement item, and current code requirements for decking attachment can qualify as a code upgrade. Spot repairs cost far less than the full re-deck an ignored leak eventually forces.
Important Distinction
Note: Decking condition cannot be fully known before tear-off: rot and delamination hide under the shingles, which is why decking appears in honest estimates as a per-sheet allowance rather than a fixed total. An estimate that promises zero decking cost is promising knowledge nobody has yet.
Dealing with this on your own roof? Call (512) 893-7663 or get an instant online quote — Zilker Roofing inspects before recommending. Honest assessment, no pressure.
Also Known As
These are the search terms and phrases that commonly refer to this topic, so you can find it however you describe it.
How Roof Decking Relates to Other Topics
Rotten decking cannot be seen until tear-off exposes it, which is why decking replacement is the most common mid-job supplement - no honest bid can price wood nobody has seen yet.
Chronic attic moisture from starved ventilation delaminates decking from below - the tell is dark staining on the underside of the roof deck, visible from inside the attic long before the roof surface shows anything.
A nail is only as good as the wood it grips: nails driven into rotten or delaminated decking back out over time, and each backed-out nail lifts the shingle above it into the wind.
Decking condition discovered at tear-off is the main reason a replacement's final cost can differ from its estimate, which is why honest estimates carry decking as a per-sheet allowance.
Deck condition is checked at tear-off because every later layer depends on sound decking, and compromised sheets must be replaced before anything covers them.
Related To Roof Decking
Deck-mounted skylights fasten directly to the roof deck, so the deck's condition around the opening matters before installation.
Tear-off is the only inspection of the decking a roof ever gets - soft spots, delamination, and rot are found underfoot after the shingles come off, not from the driveway or the attic hatch.
Decking is the layer everything else nails to, which makes it the one layer no shingle or underlayment upgrade can compensate for - fasteners in soft wood hold nothing, however premium the material above them.
When the old roof comes off, many jurisdictions require the exposed decking be re-nailed to current fastening schedules before anything new goes on - a code-upgrade cost that only exists because tear-off made the decking reachable.
Questions about Roof Decking?
Zilker Roofing inspects before recommending. Honest assessment, no pressure.