At the corners, the house isn't completely perpendicular. To be honest, there isn't a single right angle in the house.
The drywall is flush at the bottom in the corner, but higher up towards the ceiling, the gap becomes about 1 cm. Since I did this myself and am only gifted with two hands, it was quite difficult to achieve better precision on the ordeal. Otherwise, the board would have had to be cut into the shape of a parallelogram.
Does anyone know the best way to fill this gap?? Cutting small wedges out of drywall is doomed to fail because you can't screw them in place.
Housefix or tile fix or equivalent could work?
The wall will then be moisture-proofed and tiled.
Can one skip filling and just use corner tape and putty? After all, it's only about 10 mm. It will be covered by tiles.