Cracks in the concrete of the ceiling

Hello everyone,

I am new to the forum. I came across the forum because there is again a problem at the construction site (the house is being built with bricks; not a prefabricated house), but I am looking for a way to get an assessment of whether this is really a serious problem without immediately hiring an expert again who charges about €400 per visit (long travel. House in a very rural area).

Last Friday, the ground floor ceiling was constructed. Yesterday (Tuesday), I noticed that many small (small in both length and thickness) cracks have formed over the entire surface of the ceiling. I have photographed the largest one.
My question now is: Is this something serious? Does it need/can it be repaired? What could happen in the worst case?
I had asked the builder whether the concrete would be kept moist over the weekend. He said no, that this was only necessary in midsummer.
But over the weekend, we had about 20°C during the day and around 0°C at night.
The floor slab and basement ceiling do not have such cracks.

I look forward to advice.
Thank you!

Regards, Saskia

Hello Saskia,

a crack width of more than 0.3 mm should be re-treated. The crack in one of the pictures shows, in my opinion, a significantly wider crack.
Here I would indicate the defect for crack injection.
Smaller shrinkage cracks are common and should be considered normal.

I hope I have been of some help to you.

Best regards