A closure consisting of a bifold door which is weight balanced in any given position and which, when fully opened, occupies the minimum of space. The door consists of two unequal rectangular bifold sections, the smaller of said sections being the upper section and is pivotally attached along one longitudinal side to the frame or beam at the top of the opening to be closed and the other longitudinal side is pivotally attached in an opposite pivotal direction to the lower, larger rectangular section. The lower section is connected by a system of cables and pulleys to a counterweight which applies an upward force to the bifold door which is equal to the weight or downward force of the bifold door when in a closed, or a partial or fully opened position. When fully opened, the upper rectangular section has pivoted to a position at right angles from its closed position and the lower rectangular section has pivoted 180.degree. in relation to the upper section so as to be folded directly under said upper section. The door may be opened or closed electrically or manually, and when closed, locked in a stationary position.