I was on a roof in Provo yesterday and my foot literally went through the plywood. That’s a bad day for everyone. Rotted roof decking is the "silent killer" of roofing systems. Homeowners focus on the shingles because they can see them, but it’s the wood underneath that does the heavy lifting.
If your decking is soft, rotted, or delaminated, your nails won't hold. And if your nails don't hold, the next big windstorm is going to peel your new roof off like a banana skin. Let’s talk about when you can save the wood and when it has to go.
The "Sponge Test" for Roof Wood
During a forensic roof inspection, we look for sagging between rafters. If the wood feels like a sponge when you walk on it, it's finished. This usually happens because of long-term leaks or, even more commonly, poor attic ventilation. Heat and moisture build up in the attic and cook the plywood from the inside out until it loses all its strength.
Wrapping it up
Never let a contractor shingle over bad wood. It is against code and it is dangerous. It might cost a little more now to swap the sheets, but it saves you from a total failure later. Stay safe up there!
