Identifying a soft or spongy roof deck is critical for maintaining your home’s structural integrity. These symptoms typically indicate that the underlying wooden sheathing (plywood or OSB) has begun to decay due to moisture penetration.

According to the provided guide, the primary signs of a soft or spongy roof deck include:

• Physical Sensation: Feeling “springy” or soft spots while walking on the roof surface.
• Visual Dips: Noticeable dips or sags in the roofline, which suggest the decking has lost its structural integrity.
• Shingle Condition: Presence of curled or missing shingles, which create entry points for water to reach and soften the wood beneath.
• Attic Indicators: Inside the attic, you may find visible sagging of the ceiling or rafters, dark spots on the wood, or even daylight shining through gaps in the decking boards.
• Interior Warnings: While they may not feel “spongy” from inside, ceiling water stains (brown or copper-colored rings), peeling paint, and bubbling plaster are often the first signs that the decking above has absorbed significant moisture and is compromised.

Because these issues can lead to structural failure, it is recommended to have a professional on-site inspection to determine if the rot is localized and repairable or if a full decking replacement is necessary.

• Rotted Roof Decking: Complete Guide to Signs & Repair