Cracking plaster on the inside of external wall

[AmateurChris]

Hi there,
Newish home owner here. Since I moved in 9 months ago I'm hearing the occasional click/tick in the mid morning, a sound which appears to be manifesting itself in cracking plaster (As per photos).
This is within a built in cupboard on an upstairs external wall in the middle of the house, which is a 1960 semi (party wall is opposite side) which I believe has had cavity wall insulation done. Adjacent to this cupboard is an upstairs and downstairs bay window window which has seen some very minor plaster cracking on corners upstairs and downstairs on the side where the cupboard is (that might be unrelated but I haven't seen it elsewhere). This side of the house faces the sun in the morning.
I can't see anything obvious on the external brickwork.
My question is, is this worth investigating and who should I involve? A structural engineer? The fact this has been happening throughout the summer tells me its not water related, and the fact its happening in the morning facing the sun suggests to me the heat might be involved?

Photos in the order of top of cupboard, top of cupboard up close, ceiling of cupboard, bottom half of cupboard x 2

 

[tomfe]

Are you sure the sound you are hearing is not just plastic guttering/ fascias, soffits expanding in the sun?

 

[THughes]

You currently have pretty minor cracking that could be as a result of a change in loading from a previous occupant (loft, bedroom, footfall) through to changing curtains or equally nothing.

All houses move and this may be historic, but hasn't been noticed. I personally would monitor the cracking by taking photographs and marking two lines say 100mm apart on the wall now and they remeasuring this distance in a few weeks.

Plaster cracking would by unlikely to be audible. Its more likely that the wood frame is expanding and contracting as the sun hits it due to its lower thermal capacity.

However if you do see a significant change you will need to investigate further and a structural engineer would be a good place to start. Your home insurance may cover such costs or have a procedure in place for such issues.

If you post up some more photos of the layout, external views (brickwork and elevations ) and your cracking downstairs myself or others may be able to advise further.