ᐅ Crack in basement ceiling is getting larger—who should I contact?

The only major work done was renewing the screed in the bathroom to install underfloor heating. Otherwise, laminate flooring was laid, some cables were installed, and the basement windows were replaced. Apart from that, no significant changes were made.

Would it be best to have a structural engineer check it?

Since no professional has responded here, I will try to offer some advice as an amateur. Could it be that this is not an in-situ concrete slab but rather made of concrete panels placed in sections? Do you have additional joint lines for filling at regular intervals? It would, of course, be unfortunate if a panel joint is exactly at the opening for the stairway. However, since I suspect there is an exterior wall very close by, I would say the ceiling is probably stable. I just cannot explain why it is still shifting after such a long time.

So, is the bathroom located directly above where the screed was newly applied? Or at least diagonally above it? Then that could be the reason.

KellerMaus schrieb:

For me, it’s mainly important to know whether the crack could be dangerous or if it can simply be filled over.

I don’t consider such cracks to be dangerous. If you’re uncertain, consult a structural engineer.

In der Ruine schrieb:
Since no professional has responded here, I’ll try to give advice as a layperson. Could it be that this is not a cast-in-place concrete slab, but rather made of precast concrete panels laid in sections? Do you have additional joint lines filled with putty at regular intervals? It would be unfortunate if a panel joint happens to be right at the hole for the stairwell opening. However, since I suspect there is an exterior wall nearby, I would say the slab is likely properly supported. I can’t explain why it is still moving after such a long time, though.

That’s exactly the case. There are multiple panels, and the putty joints appear at regular intervals. And yes, as you can see, there is a panel joint right at the staircase opening.

My layperson’s explanation is simply this: Previously, only one person lived in the house; now, four people live here and the building is used very differently. Above this is the staircase to the upper floor, which probably had little use before and is now used regularly.

Tolentino schrieb:

Is the bathroom located above where the screed was newly applied? Or at least diagonally above? That could explain it.

The bathroom is to the right of the stairs. But that work was done last year between March and May.