Abstract: A door assembly including a door having a top, bottom and side rails along each longitudinal edge of the door, at least one hinge to be secured to the door, and means, to the at least one hinge, to be secured to a door frame to mount the door, the side rails having channels running along a substantial length of the door opening at the top or bottom, of the door, the said channels being of a configuration to accommodate the at least one hinge, the at least one hinge having a hinge flange being adapted to be secured to, or removed from, the door only by sliding it from the top or bottom portion of the channel into position, and fastening means for securing the flange of the at least one hinge to the bottom of the channel upon being driven through said flange and the bottom of the channel into the door, when said flange is positioned in the channel.