Hello, why do you want to insulate the attic? So your boxes don’t freeze? :) No one can give you a plan for the exact construction and materials from a distance. You would have to take a closer look at the surroundings. At the moment, you probably don’t have any moisture problems, and to keep it that way, you need to consider a few things. What about the exterior walls? Should they remain cold? Half-timbered walls are not easy to insulate. Proper planning and material selection are required. What does the ceiling of the top floor look like? Is it vapor-permeable? Is there a vapor barrier? If yes, is it correctly connected? Warm, moist air always gets into the attic, and if you plan/execute your construction incorrectly, you will have problems. The air must somehow be able to escape… very important!!!! So I would reconsider the insulation. And if it absolutely has to be done, get a professional who can look at everything on site and tell you how you should do it. Regards