How do I Know if my Roof Decking is Rotted?

Identifying rotted roof decking early is essential to prevent structural failure. Because the decking (the plywood or OSB sheathing under your shingles) is hidden, you must look for both interior and exterior warning signs.

Interior Warning Signs

Your home’s interior often reveals damage before the exterior does. Look for:

• Ceiling Water Stains: Brown or copper-colored rings, peeling paint, or bubbling plaster.
• Attic Clues: Visible mold growth, dark streaks on rafters, damp or compressed insulation, and rusty nail tips poking through the sheathing.
• Odors and Gaps: A persistent musty smell or visible daylight shining through gaps in the attic boards.

Exterior Warning Signs

From the outside, you can spot physical changes to the roof’s structure:

• Physical Texture: Spongy or “springy” spots when walking on the roof, or visible dips and sags in the roofline.
• Shingle Condition: Curled, cracked, or missing shingles that allow water to penetrate the wood.
• Eave Damage: Visibly rotting wood or soft boards at the fascia and eaves.

Because decay can be silent and spread rapidly in wet climates, the best way to confirm the condition of your decking is through a professional on-site inspection involving photo reports and attic evaluations.

• Rotted Roof Decking: Complete Guide to Signs & Repair