A two storey office is particularly useful for businesses that carry out two or more types of work or services.
The ground level must be retained for business that needs frequent outings and or client visits while the top floor is kept for quiet business work. Keeping that in mind allot the ground floor for the reception, marketing, hardware services and administration and the upper storey for software development, accountancy or similar such work that needs quiet environs.
Keep ample passageways and proper stairways for foot traffic as well as during emergencies. Since the upper storey is connected mainly through the ground level it is mandatory to create fire escapes on the upper level too. Similarly both levels should have a conference room, pantry, water coolers and bathrooms.
Allocate enough space for various departments and their heads on each floor. Use similar wall colors and other décor elements to tie both levels together.