To construct more buildings or structures than are necessary or sustainable in a given area. The city decided to overbuild in the downtown area, leading to a surplus of office space.
To build something in a way that is excessively complex or robust, often more than is needed for its intended purpose. The engineer chose to overbuild the bridge to ensure it could withstand any potential natural disasters.
To construct a new structure directly above or on top of an existing one. Developers plan to overbuild the railway tracks with a mixed-use complex.