My Question(s) - : Is spongy plywood on a 20 year old roof OK or does it need to be replaced? This plywood was solid 5 years ago.
More background (edited based on comments):
I was walking on my roof last week and it is spongy all over (like walking on carpet with a reallllly good pad). 5 years ago it was solid (far more solid - definitely had some flex). There are no leaks to speak of (that I know) except a gasket that was worn around the sewer air intake drain that I corrected as soon as I found it 3 weeks ago, but not sure how long it was happening. It's a split level and the other half (that is dry) is equally spongy). I got a quote and the guy walked the entire roof and acknowledged that it was spongy, but said 3 pieces of plywood would need to be replaced. Can a 20 year old roof that was solid 5 years ago and is spongy now only need 3 sheets of plywood. Another estimator told me the golden beads along my joists in the attic were sap from the plywood. My guess is that I need to replace most if not all of the plywood.