I am trying to sort a wall out that has been coated in bitumen many years ago. The bitumen is no longer on the pointing and at some stage it has been redone badly some of the old mortar is showing as a result. The mortar is saturated and unstable so I am guessing rain water is finding the weakest points and over time has found its was to the inner leaf of th cavity. The inner wall at the lowest point in the building has moisture in the wall to about 6ft, it is not rising damp my guess is that water has got in and the untreated bricks are acting like a sponge. So My question is, without repointing the wall is it possible that ventilating the cavity will help the moisture to escape? And allow the internal wall to dry? and if so what would be the best method to do this? Any help will be appreciated thanks. Just to add I assume it is a cavity wall but the building is over 100 years old so could I be wrong?

It might help a little, but you need to sort the pointing out first.

Not to worry I have installed two airvents as the room doubled as a kitchen and the problem wall was the coldest as it had no cavity or Insulation making this the coldest and causing condensation to settle on that wall only, thanks anyway.