Abstract: A sliding door system 11 can include a sealing mechanism 40 such that, when a door panel 10, 10a is slid to a closed configuration 100, one ore more seal elements 42 are extended to form a seal between the door panel 10, 10a and it surroundings at the bottom, top and/or sides of the door to reduce or prevent infiltration of gases or liquids such as air or water. Manual or motor driven movement of the door panel 10, 10a can automatically move an actuation mechanism 50, 50a to extend the seals around the door. The sealing member 40 can include weather stripping, brush or another seal element 42 that is extended into sealing contact with a floor 6 or other surface. Multiple door panels 10, 10a including the sealing system can be arranged to form a door panel system 11.