Thank you Millymollymama
This is a copy of the insurance report conclusions:
Discussion
In this case there is no evidence of foundation movement. The damgae may be due to differential movement between dissimilar materials possibly between the timber roof structure and the the supporting masonry.
Timber is vulnerable to changes in moisture, rather than temperature. It shrinks and swells in relation to changes in humidity.
Seasoned timber shrinks initially as part of the drying process and then undergoes seasonal changes.
Restraint has the effect of increasing dress locally. Forces (a0 dissipate through the wall or (b) cracks develop due to release of tension or failure in compression or shear. Restraint attempts to reduce movement. For example, cracks will appear where a strong masonry unit, with rich cement mortar abuts a block wall, with weaker mortar.
In short, strong parts of the building impose restraints on weaker parts and these result inserts. Sometimes this stress produces cracking.
Recommendations
The damage is not due to an insured peril. The insurance policy provides cover for the repair of damage resulting from foundation movement. In this case I saw no evidence of either subsidence or heave that appeared recent.
We will go ahead with the structural engineers report. At least we'll
know one way or another.