A flood-proof door (1; 20) for a building comprising: a door frame with a first sealing member provided around an outer periphery; a hinged door pivotally mounted to the door frame and with a second sealing member provided around an outer periphery; wherein: the hinged door comprises an outer frame formed of PVCu enclosing one or more door panels also formed of PVCu; the outer frame of the hinged door defines an internal volume; within a lower portion of the hinged door free space within the internal volume of the outer frame is substantially filled with a waterproof foam; and the outer frame of the hinged door further comprises an internal reinforcing member located within the internal volume; and a locking system substantially formed along a closing side, lower side and hinged side of the hinged door and comprising at least one locking means in a closing side of the hinged door, at least one locking means in a lower side of the hinged door and at least one locking means in a hinged side of the hinged door, wherein all of the locking means (10, 13, 13) of the locking system are operated by a single locking mechanism through a system of cams and sliders; wherein, when the hinged door is in a closed position within the door frame, the first sealing member provides a first watertight seal between the hinged door and the door frame and the second sealing member provides a separate second watertight seal between the hinged door and the door frame. a door frame with a first sealing member provided around an outer periphery; a hinged door pivotally mounted to the door frame and with a second sealing member provided around an outer periphery; wherein: the hinged door comprises an outer frame formed of PVCu enclosing one or more door panels also formed of PVCu; the outer frame of the hinged door defines an internal volume; within a lower portion of the hinged door free space within the internal volume of the outer frame is substantially filled with a waterproof foam; and the outer frame of the hinged door further comprises an internal reinforcing member located within the internal volume; and the hinged door comprises an outer frame formed of PVCu enclosing one or more door panels also formed of PVCu; the outer frame of the hinged door defines an internal volume; within a lower portion of the hinged door free space within the internal volume of the outer frame is substantially filled with a waterproof foam; and the outer frame of the hinged door further comprises an internal reinforcing member located within the internal volume; and a locking system substantially formed along a closing side, lower side and hinged side of the hinged door and comprising at least one locking means in a closing side of the hinged door, at least one locking means in a lower side of the hinged door and at least one locking means in a hinged side of the hinged door, wherein all of the locking means (10, 13, 13) of the locking system are operated by a single locking mechanism through a system of cams and sliders; wherein, when the hinged door is in a closed position within the door frame, the first sealing member provides a first watertight seal between the hinged door and the door frame and the second sealing member provides a separate second watertight seal between the hinged door and the door frame.