Functionality in building design means whether the design serves its purpose well. For a sustainable building, we wish to create pleasing, functional and comfortable space using materials and methods that have the least possible effect to the environment. The function of the building should last for a long period of time while the building should continue to operate in a manner that keeps its environmental impacts as low as possible. In other words, the design must provide rooms for future improvement in technology advancement and should be flexible and adaptable to the changing tenant requirements. The following are examples of flexible building design:

1. Multi-function rooms and flexible fit-out
2. Switchboard spaces at the building’s switch room that can caters for additional needs of new electrical appliances due to technology advancement
3. Use suitable structure
4. Floor height and layout that suit the purpose of the design