One-Piece Sill Pan Flashing

A one-piece sill pan flashing is provided with accordion sections enabling the flashing to be adjusted in width as necessary for installation in rough framing. The new flashing includes a sill plate cover with forwardly and downwardly inclined upper portions and lower portions extending downward from the upper portions. The accordion sections are incorporated integrally into the sill cover and are formed of narrow panels, flexibly connected along lateral edges to form V-shaped accordion folds having a series of ridges and valleys. The respective ridges and valleys are aligned in common vertical planes and are rounded through a transition curve at the front corners thereof. The flashing is injection molded in two end parts, each with one or more accordion sections. Center extensions can be used for extra wide window framing. The parts are permanently bonded and sealed at the factory and shipped and installed as one piece.