pregraditi

1. to partition; to divide off
   Pregradili smo sobu da svako dete ima svoj deo. — We partitioned the room so each child has their own part.
2. (of a road, river) to block; to dam
   Kamion je pregradio ceo put. — A truck blocked the whole road.
   Reku su pregradili branom. — They dammed the river.

The imperfective is pregrađivati.