Minor cracks in mortar

[Rob broom]

Hi.

There are few photos attached.

Can I get some advise on what cause these cracks please?

the blocks have been in place for about 2 or 3 months.

the cracks are less than hairline.
mortar mix was 4:1 sand cement with additive.

Is it any if the following reasons?
Thermal.
Shrinkage.
Drying out.
Minor Settlement.
Mortar mix ratio.
Damp blocks during building work.

or, a sign of more scary things like foundation issues?

Any advice would be great as I am low in experience.

thanks

 

[Rob broom]

 

[stuart45]

With blockwork it's generally shrinkage cracking as they dry out. Blocks are normally at their largest when laid, clay bricks at their smallest.

 

[Rob broom]

Thanks for the reply!

fingers crossed that it is nothing more than that.

the other thing I should add is that the blocks were all stored outside and uncovered, and I didn’t cover the walls while i was building them.

hopefully this all adds to the evidence of them being wet and drying out!

thanks again!