I firgured this one is long overdue, but I also cover it in my
video:
How to EDIT buildings with the 'special roof' treatment? (overhang, drawings on facade, diagonal roof edges etc.) If you just start remodeling the inside of the buildings, the roof parts will disappear. (Only for adding/removing/editing rooms, fences etc. So only STRUCTURAL changes, redecorating is no problem)
1) A few examples of these 'special' roofs (how it is built, I explained earlier). If you add a wall inside the structure somewhere, you can easily see which roofs disappear!
https://i.imgur.com/OvxgEy7.png
2) Pull the roof parts completely out of the house, they cannot touch the main structure anymore. Keep in mind, this means: no being present below overhanging platforms, no floating above decks, no diagonal touching to any of these either! For the pulling, just use the arrows to make the roof parts wider and then make them smaller again once outside.
https://i.imgur.com/2aQAYs4.png
3) Edit the building to your liking and afterwards drag the roofs back to their original place.
https://i.imgur.com/Iz819mz.png
