Damp proofing advice for old apartment needed

I need to get an old apartment completely damp proofed. It’s a place we were going to sell but :roll: so I’m going bite the bullet and do it up and hope to let it again.
The problem is its ground floor, old (about 12yrs) and showing some bad signs of damp.
I’m just starting to do some research and look for the best way go about it. ( as don’t know the first thing about where to start.)
All advice and recommendations welcome!!!

If it's only 12 years old it almost certainly has a damp-proof course so it's probably not rising damp that's causing the damp problems.

It is more likely to be internal damp caused by condensation, which is usually caused by poor ventilation, cold walls, drying clothes indoors, not venting bathrooms properly etc.

I'd look at these fixes first i.e. ventilation of bedrooms and bathrooms, keeping a low level of heating on etc. before looking at damp-proof course.

As Sherman said, this more than likely is not the DPC ....... unless you've raised the ground outside with paving, rockery etc. These, as with faulty guttering, broken downpipes etc. will cause lateral penetration dampness. But I think your problem is on the inside. Is the kitchen used for a lot of cooking without the cooker hood being turned on? Baths/showers taken with the bathroom door open? Lots of ways of causing moisture indoors. Finally, if the walls are solid (render on block) then they will be cold ........ and thus condensating the moisture-laden air when it comes into contact. If so, you need to insulate internally.

Interesting points there, thanks. Thinking about what you said, I think I pay be an external damp problem.
The building itself is older, it was converted into apartments but I imagine the original external walls a much older. The damp problem is mostly below window level, and actually the worst spot is where there has been rockery / shrubs planted against that external wall!! Bathroom itself has some signs of damp but not as bad as the external walls.
Possibly it is an internal insulation problem, I think I’ll have to get a professionals advice. Any recommendations ?

If you are on the East coast try Brendan 087 264 0066. A no nonsense reliable small builder.