A method of forming a folded panel, the method comprising: - one of (a) forming a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) by securing an outer layer to a first major surface of a fiber-reinforced polymer-, FRP-, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface with a polymer matrix at least partially covering the second major surface, and (b) providing a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) with an outer layer secured to and covering a first major surface of a fiber-reinforced polymer, FRP, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface and with a polymer matrix at least partially covering the second major surface; - folding the multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) about a fold line (20;) to create opposed plies (22A, 22B) on either side of the fold line (20;) with the polymer matrix of one of the opposed plies (22A, 22B) contacting the polymer matrix of the other of the opposed plies (22B, 22A) and with the outer layer forming a folded edge at the fold line that is continuous with the outer layer covering the opposed plies (22A, 22B); and - consolidating the FRP substrate (15A, 15B, 15C) of the folded panel (10; 10'; 10"; 60, 10A, 10B; 80) to form a folded, consolidated panel (28, 28'; 28A; 28B; 75, 75A, 75B; 95). - one of (a) forming a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) by securing an outer layer to a first major surface of a fiber-reinforced polymer-, FRP-, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface with a polymer matrix at least partially covering the second major surface, and (b) providing a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) with an outer layer secured to and covering a first major surface of a fiber-reinforced polymer, FRP, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface and with a polymer matrix at least partially covering the second major surface; (a) forming a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) by securing an outer layer to a first major surface of a fiber-reinforced polymer-, FRP-, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface with a polymer matrix at least partially covering the second major surface, and (b) providing a multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) with an outer layer secured to and covering a first major surface of a fiber-reinforced polymer, FRP, substrate (15A, 15B, 15C) having a second major surface opposite the first major surface and with a polymer matrix at least partially covering the second major surface; - folding the multi-layer panel (10; 10'; 10"; 10, 60; 10, 80) about a fold line (20;) to create opposed plies (22A, 22B) on either side of the fold line (20;) with the polymer matrix of one of the opposed plies (22A, 22B) contacting the polymer matrix of the other of the opposed plies (22B, 22A) and with the outer layer forming a folded edge at the fold line that is continuous with the outer layer covering the opposed plies (22A, 22B); and - consolidating the FRP substrate (15A, 15B, 15C) of the folded panel (10; 10'; 10"; 60, 10A, 10B; 80) to form a folded, consolidated panel (28, 28'; 28A; 28B; 75, 75A, 75B; 95).