A flood barrier shield system for installation in a building opening such as a door frame includes a water impervious panel having a base edge and at least two side edges generally complementary in shape to the base and side edges of the opening into which it is to be installed. Channel shaped seal housings are mounted on the panels adjacent its base and side edges which contain seal bars consisting of a relatively rigid bar having a flexible seal mounted thereon and extending the length of the housing. The seal is located to face the opposing surface of the opening and the bar is connected to the housing by selectively operable devices which move the bar and seal between retracted and extended position for ease of positioning the flood barrier in the opening and then forming a water tight seal along the base and sides of the system.