Easier said than done, of course, because our house, although big enough, is already full to the nook. So a big reorganization was necessary, first moving lots of 'stuff' to the place under the roof. We needed three rooms altogether, or rather four.
For the first room, 'the atelier' (workplace) itself, a tiny guestroom and bathroom had to be joined. Those two rooms were in use as sewing room and garderobe room respectively. Here you can see a glimpse of the old situation, it took a few days to empty it:
And then the demolition fase:
The ceilings had different hights, and so did the floors.