Roof decking is the wooden surface attached to your roof trusses. Every roofing component — underlayment, shingles, flashing, and vents — is installed on top of this layer.

If roof decking fails, the entire roof system fails.

Common Decking Materials

• Plywood

• OSB (Oriented Strand Board)

• Plank decking in older homes

Why Decking Gets Replaced During Roof Replacement

During tear-offs, roofers often find damaged decking caused by leaks, moisture, or poor ventilation.

Signs of damaged decking include soft spots, sagging roof sections, attic mold, and shingle waves.

Why This Matters

Shingles are only as strong as the wood beneath them. Skipping decking repairs during a roof replacement can lead to early roof failure.