Ventilation when slab in place

Evening,

Have an 1870 terrace in Sydney with some dampness / condensation issues on an internal wall.

After a lot of reading I have come to conclusion that it is due to condensation
- external wall rendered
- no vents external or internal
- concrete slab with floorboards a few cm above

Is it worthwhile trying to get ventilation into this very narrow gap between slab and floorboards?

Thoughts on air brick internally?

Any other tips?

Thanks 🙏

Presumably the terrace contains similar houses of similar construction?. Have you asked the other terrace residents if they have a similar issue and how they have addressed it?

I used to live in an old terrace in the inner west which had a sub floor fan whirring on a timer-it did have vent to the outside though-from memory below the front room window. Have a look at the neighbours external front wall-you never know, someone may have got the idea that to prevent damp it would be a good idea to the seal vents....