A panel assembly including: a first sheet member of generally rectangular configuration having a first and a second edge portion, the edge portions being generally parallel and transversely spaced, and a third and a fourth edge portion, the third and fourth edge portions being generally parallel and transversely spaced and generally perpendicular to the first and second edge portions, a central sheet part extending between the edge portions, with at least the first and the second edge portion extending from the central part in a direction generally transverse relative of the central part; a second sheet member of generally rectangular configuration having a first and a second edge portion, the edge portions of the second member being generally parallel and transversely spaced, and a third and a fourth edge portion, the third and fourth edge portions of the second sheet member being generally parallel and transversely spaced and generally perpendicular to the first and second edge portions of the second sheet member, a central sheet part extending between the edge portions of the second sheet member, with at least the first and second edge portions of the second sheet member extending from the central part of the second sheet member in a direction generally transverse relative to the central part of the second sheet member; and wherein the first and second edge portions of the first sheet member are engaged with the first and second edge portions of the second sheet member, with the first and second edge portions of the first sheet member being located between the first and second edge portions of the second sheet member and being engaged therewith to apply outward forces to the second sheet member so that the central part of the second sheet member is under tension: wherein the first and second edge portions of the first sheet member are resiliently deformed so as to engage the first and second edge portions of the second sheet member to tension the central part of the second sheet member. a first sheet member of generally rectangular configuration having a first and a second edge portion, the edge portions being generally parallel and transversely spaced, and a third and a fourth edge portion, the third and fourth edge portions being generally parallel and transversely spaced and generally perpendicular to the first and second edge portions, a central sheet part extending between the edge portions, with at least the first and the second edge portion extending from the central part in a direction generally transverse relative of the central part; a second sheet member of generally rectangular configuration having a first and a second edge portion, the edge portions of the second member being generally parallel and transversely spaced, and a third and a fourth edge portion, the third and fourth edge portions of the second sheet member being generally parallel and transversely spaced and generally perpendicular to the first and second edge portions of the second sheet member, a central sheet part extending between the edge portions of the second sheet member, with at least the first and second edge portions of the second sheet member extending from the central part of the second sheet member in a direction generally transverse relative to the central part of the second sheet member; and wherein the first and second edge portions of the first sheet member are engaged with the first and second edge portions of the second sheet member, with the first and second edge portions of the first sheet member being located between the first and second edge portions of the second sheet member and being engaged therewith to apply outward forces to the second sheet member so that the central part of the second sheet member is under tension: wherein the first and second edge portions of the first sheet member are resiliently deformed so as to engage the first and second edge portions of the second sheet member to tension the central part of the second sheet member.