Recently had a single skin wall built to replace an existing single skin externall wall that was spalling badly, only small, probably about 2 meters wide with a door in it. Engineering commons were used for the wall, the internal wall was rendered with sand/cement, about a 3/4 days later the finish coat was applied. I've left it to dry for about two weeks and I am starting to get some efflorescence appering on the plaster, it seems worse around the angle beads to be honest. Any ideas or suggestions? I ideally want to paint the wall soon, but not if it's going to cause the paint problems.