build on phrasal verb ( see also ↑ build )
1 . build something on something to base something on an idea or thing:
Our relationship is built on trust.
2 . build on something to use your achievements as a base for further development:
The new plan will build on the success of the previous programme.
3 . to add another room to a building in order to have more space
build something ↔ on
We’re planning to build on a conservatory.