A panel member (17; 85; 51; 58) for architectural openings (3), includes a perimeter frame defined by first and second frame posts (19, 21, 37, 39; 79, 81, 59, 61), and upper and lower frame beams (23, 25, 41, 43; 87, 91, 63, 65). The perimeter frame of the panel member (17; 35; 51; 53) defines an inwardly opening slot (19B, 25A, 39B, 43A; 61B, 65A) Coextensive first and second plates (27A, 27B, 45A, 45B; 83A, 88B, 67A, 67B) are held in the respective inwardly opening slot to be relatively slidable with respect to each other. A resilient strip (99) is accommodated within each of the first and second frame posts (19, 21, 37, 89; 79, 81, 59, 61), and positioned to extend between an inner wall of the respective first and second frame posts and an outer surface of the respective one of the coextensive first and second plates (27A, 27B, 45A, 45B; 83A, 83BS 67A5 87B), as well as longitudinally of each first and second frame posts. A folding panel assembly (1) for architectural openings (8), includes at least one such panel member as first or second panel members, a mounting post (11; 77) for mounting to a substantially vertical perimeter portion of an architectural opening. A first hinge (15; 75) is connected to the mounting post (11; 77), and the first panel member (17; 51) has its first frame post (19; 79) pivotally mounted by the first hinge. A second hinge (83; 55) is connected to the second frame post (21; 81) of the first panel member, and the second panel member (35; 53) has its first frame post (37; 59) pivotally mounted by the second hinge (33; 55),