Which professional category repairs a flat concrete roof above a garage?

[Thomas_Blekinge]

The said concrete roof is cast, probably with rebar, spanning about 3.5 meters. It has become leaky and lets rainwater through in some places. I assume the rebar is corroded there.
Which profession assesses and repairs this? It might be a local crack that can perhaps be recast in some way. This isn’t a carpenter's job, is it?
Of course, it should be sealed from the top afterward.

 

[Plupp 405730]

The said concrete roof is cast, probably with rebar, span about 3.5 m. It has become leaky and lets rainwater through in a few places. I assume the rebar is damaged there.
Which professional category assesses and repairs this? It could be a local crack that might be re-cast in some way. It's probably not a job for the carpenter?
Of course, it should be sealed on the top side afterward.

Concrete and masonry companies usually repair concrete...