Periodic Popping noise in roof structure

I have a project where I’ve owner is hearing periodic popping noises in the roof structure. I have the structural drawings from the early 90’s and it is a plant manufactured wooden roof truss system. The owner says that the popping is coming from two areas of the roof. In one of the areas a large girder truss is suspect, and at the other location a hip master is suspect. The noises started recently after 30 years or no.

There have been no instances where trusses were overloaded, and there are no signs of any sliding or rotational shifting of the foundation.

I am suspicious that the ends of the two trusses may be periodically sliding suddenly due to temperature changes, but why after 30 years, and why both trusses at the same point in time? Seems very odd to me.

I have checked on the attic and could see nothing of any consequence from what I could see.

I hate puzzles I cannot definitively solve for the client. Any thoughts or similar experiences?

I am continuing to study the drawings as the situation is puzzling to me and the owner is very disconcerted.

I have basically the same situation, and same noises, but I’m not worried about it.
It is always thermal expansion/contraction.

The amount of popping and cracking changed each time I changed the roof shingles. Darker = more heat absorption, lighter color = less.
Cold winter = more heating = greater differential between inside and outside temperatures.

If you keep investigating and discover anything important that I’ve missed, please let me know!

I would not put much weight in the “this just started” statement. More likely that it was just “noticed” recently. Sounds due to thermal expansion that occurs when a cloud obscures the sun are very common but seldom noticed. Once noticed, it then becomes notable. Gas discharge street lamps turn-off due to overheating when they age and will turn back on when they cool. Few notice this. I had an engineer friend who insisted that the lamps would go off when he approached.

Vinyl siding is notoriously noisy due to its high CTE, and probably improper installation, which didn’t allow for expansion.