My brother added an extra upper room in their house for his office and semi-workout/exercise room. He finds it very confining to have an office in their ground floor because the area is very limited. He designed an attic at the top of their second floor and to maximize space he supplied a small straight stair that will occupy very small area only. When I visited him after the attic was constructed I was impressed at how he made every corner of the attic very useful. He made a stock room for his blue printing business and managed to squeeze some gym equipment on the other side. Since it’s the highest space in the house it also brings more air when you open the windows so my brother can work also in comfort.