Abstract: An extruded aluminum sill member is supported by and attached to a wood base member which also supports a longitudinally extending inner wood trim member. The sill, base and trim members define a longitudinally extending cavity which receives a vertically adjustable rail member. The rail member has longitudinally spaced captive screws which are threaded into inverted T-nuts confined within laterally extending slots formed within the wood base member, and the trim member covers the slots. The sill member also extends under a jamb or mullion and a fixed side panel, and a snap-in extruded plastic cap covers the cavity under the panel and has an upwardly projecting and inwardly curved flange with a flexible lip for engaging the outer surface of the panel to form a water-tight seal.

Abstract: An extruded aluminum elongated sill member is supported by a wood base member and includes a sloping top wall integrally connected to a lower base wall positioned within a recess in the wood base member. A longitudinally extending wood trim member is attached to the wood base member and cooperates with the lower base wall to define a longitudinally extending cavity which receives a vertically adjustable rail member. The sill and rail members define corresponding longitudinally extending adjacent slots, and a longitudinally extending sealing member of extruded plastics material includes opposite semi-rigid edge portions with flexible fins which are pressed into the slots. The edge portions are integrally connected by a flexible U-shaped intermediate portion which is confined between the sill and rail members and forms a rolling diaphragm for vertically adjusting the rail member while maintaining a positive water-impervious seal therebetween.