Compression gasket flood barriers offer a 100% watertight seal against floodwaters from one or both directions.  Available for any size opening, these flood barriers utilize either drop bolts or rotating dogs to compress the gasket against the knife-edge of the frame.  The standard bottom sill is raised 2" from the floor surface, however a recessed sill with a removable flush sill plate is available.

East of installation and low maintenance make this type of flood barrier popular.  They can be designed to seal or 3 or all 4 sides.