rob wrote:
Please help solve an argument between me and my dad, I don't think
there's really that much difference between plasterboarding and
skimming a wall and plastering it properly, my dad however says that
plasterboarding and skimming causes damp where as normal plastering
wouldn't. The wall in question is an outside wall in a mid-terrace
bedroom.

You can get something called interstitial damp with a gap that is not
vented. So vent it. Both are permeable to the outside. A layer of
visquine might prevent that, in which case the plasterboard is able to
hold up to the technical stresses. Plaster would just slide off it.