While I agree that is probably just shrinkage over years... I would also say that this could be a *symptom* of other concerns that needed to be verified to be present or not present, such as the lack of or broken rafter supports or collar ties. Or, it could be overspanning of the collar ties.

There are alot of other things to check for instead of just looking at the symptoms. Look for what may have caused the symptoms from the attic side.

Rich

__________________
"If con is the opposite of pro, is Congress the opposite of progress?"
Richard Rushing, HCRI
Duncanville, Tx.