You should think about this when you design your barndominium.
It is crucial to think about the insulation and framing of the structure. You should leave enough space for the exterior of the design. A good rule of thumb is to include a one-foot section of space around the entire building.
Check that your doors and hallways be in line with your local building code. They should be at least 36 inches long. Also, you will need to set aside space for items like furnaces and water heater.
Every bedroom should be sized in order to accommodate the bed you want to use. The bedrooms also require a window or two, and you might want to add closet space instead of using wardrobes and dressers. You can reduce the size of the bedrooms, making it more important for the common rooms. Again, account for the thickness of your walls and include enough space for the plumbing, insulation and wires.
There are just a handful of options for creating the perfect barndominium. For more advice, see the linked video.