Light weight fiber-reinforced polymeric (FRP) structural building panels and panel assemblies, sized and configured for construction of non-portable wall structures permanently fixed to the ground, optionally tying overlying structure to an underlying footer through such panels and panel assemblies. Fiber schedule and fiber orientation in the panels provide enhanced properties of the panels. Fibers are typically oriented within 15 degrees of a top-to-bottom direction in the panel providing, in part, enhanced top-to-bottom crush strength of a panel/wall per length dimension related to mass of the panel/wall per unit length and/or limited deflection of the panel/wall. Panels of the invention also have a bias to deflect toward the surface of the panel which faces outwardly of the building, toward the backfill soil which faces the panel, outside the building.