Ventilate wall

[Kris1]

Hi gang,
I tore out a framed room in the spring after the drainage work, and all exterior walls are now plastered.
But then I noticed damp plasterboard at the bottom in one corner of a wall that originally (early 50s) was an outer wall. In the late 50s, an extension was built, and this wall is now not an outer wall.
Anyway, I tore off the plasterboard and noticed that the metal stud was rusty right in the corner. So, is the moisture coming from the slab?

Now I plan to install new metal studs and moisture-resistant plasterboard, but can I ventilate this wall section?

 

[Jonatan79]

How do you know for sure that the moisture came from the slab? Has the basement been unheated and poorly ventilated?

 

[Kris1]

How do you know for sure that the moisture came from the slab? Has the basement been unheated and poorly ventilated?

I'm not sure it's from the slab but I assume so.
Uninsulated slab with underfloor heating.
It has been unheated during the summer. But with the circulation on.
Ventilation in the form of natural draft with mechanical exhaust in two places.

 

[Jonatan79]

Do you also have fresh air vents? I think the damage looks old, and since you have drained, the slab is unlikely to release much moisture, with or without underfloor heating.

 

[Kris1]

Do you also have fresh air vents? I think the damage looks old and since you've drained, the slab is unlikely to release much moisture, with or without underfloor heating.

Yes, there are fresh air intakes in the room.
Okay, then I'll install metal studs and fiber gypsum and skip ventilating the wall.

 

[Kris1]

But at the same time, the Gypsum was damp in the corner, so it's not an old damage.