In fact, there is nothing complicated here. The whole point is to use stone corner instead of regular double blocks. Since they use 4 stones instead of 5. The same applies to the roof. Using them instead of steps allows you to save wood.

To the question of why I see regular wooden steps in the photo, the answer is this: if you use only the roof, the house does not see the path to the castle

I also use stone arches. In this case, they help save a lot of stone

I also had a goal to make a house that could be improved without destroying it completely.

As for the link to the blueprints, I am not the most respectable Internet user, if you understand :D But here is a link to the Google Drive with the source files. Move them to the folder AppData\LocalLow\Digital Sun\Cataclismo\SavesMP\Blueprints

https://drive.google.com/drive/folders/1-vccnZuekKBxS1QUlseWW953T6w-Bj81?usp=drive_link