Pim finished the drains that come from the gutters, and he and his dad had to replace a couple of windowsills still, since they were not deep enough for what the new thickness of the wall will be.
Then Pim removed a layer of pieces of marble someone had attached to the bottom of the wall, washed the flaky paint (painting over moss is never gonna work, people) away with a Kärcher, and filled all gaps and largest unevenness with cement so that the insulation would glue to the wall properly. The insulation has guides to place the bricks, so they have to be placed level and correct (some bricks over windows etc go vertically), this is very important.
So lots of thinking, measuring, then finally cutting a gluing with a special cement glue.
The entire back is now covered in... polystyrene :D looks total class! We still have thinner insulation to glue to the edges of the windows, screw everything down, then glue the tile-bricks.
We can't wait to move on to work on the inside, the kitchen (!!!) and the dining room. We will have to, soon, due to the weather. We've already ordered the tiles for the floor :)