What to Do
Rotted Roof Decking Found During Installation: What Happens Next
If your roofing crew finds rotted decking once tear-off begins, that's a real mid-job discovery, not a sales tactic -- decking condition generally can't be confirmed until the old roofing material is stripped away, and installing new shingles over soft or rotted wood creates safety, warranty, and moisture problems, so ask for photos of the specific damaged sheets and a clear per-sheet price before work continues.
Direct Answer
If your roofing crew finds rotted decking once tear-off begins, that's a real mid-job discovery, not a sales tactic -- decking condition generally can't be confirmed until the old roofing material is stripped away, and installing new shingles over soft or rotted wood creates safety, warranty, and moisture problems, so ask for photos of the specific damaged sheets and a clear per-sheet price before work continues.
What to Do Now
- Step 1
Ask to see photos of the specific rotted sections before agreeing to any additional cost -- reputable contractors document this rather than asking you to take their word for it.
- Step 2
Confirm the per-sheet or per-square-foot replacement price in writing, since this is normally addressed as a contingency in the original estimate rather than negotiated on the spot.
- Step 3
Understand why it matters: manufacturers generally require sound decking underneath for shingle warranties to remain valid, and nailing into rotted wood is both a structural and a safety problem.
- Step 4
Ask whether the crew found isolated soft spots or a broader pattern, since that affects both the added cost and how it happened in the first place (a prior slow roof leak is a common cause).
- Step 5
If the added cost feels high relative to the visible damage, it's reasonable to ask for the removed decking to be shown to you before it's hauled away.
Frequently Asked Questions
Is finding rotted decking during a roof installation common?
It's common enough that experienced contractors address it as a contingency in their contracts before work starts, rather than treating it as unusual. How much decking (if any) needs replacement varies a lot by roof age and prior leak history.
What does replacing rotted decking typically cost?
Published 2026 material pricing runs roughly $9-$60 per sheet for OSB and $16-$64 per sheet for plywood, with installed costs (material plus labor) commonly landing around $2-$5 per square foot -- confirm the specific per-sheet rate with your contractor rather than assuming a number, since it varies by market and decking type.
Can a new roof just be installed over rotted decking to save money?
This isn't recommended and is generally against manufacturer installation requirements -- nails won't hold securely in soft wood, and trapped moisture underneath continues deteriorating the structure even after new shingles go on top.