A sandwich-structured composite panel, comprising - a first face skin of sheet metal, providing the façade surface of the panel, - a second face skin of sheet metal, providing the back surface of the panel, and - a core arranged between the first face skin and the second face skin, the first and second face skins being attached to the core, - an upper edge, comprising an upper edge skin construed from the sheet metal establishing the first face skin, - a lower edge, comprising a lower edge skin construed from the sheet metal establishing the first face skin, - an upper attachment element arranged in the upper edge, wherein - the upper attachment element comprises a first fixing surface, - the first fixing surface being attached to the second face skin of sheet metal, wherein - the façade surface of the panel is arranged in a first angle in relation to the upper edge skin and the first fixing surface, - the upper attachment element comprises an upper extension for attaching another composite panel above the composite panel, - a lower attachment element is arranged in the lower edge, said lower attachment element comprising - a third fixing surface attached to the second face skin in the lower edge, and - the façade surface of the panel is arranged in a second angle in relation to the lower edge skin and the third fixing surface characterized in that - said first angle is more than 90°, that - the second angle is less than 90°, and that - the lower attachment element comprises a groove-like counterpart arranged in use to receive the upper extension of an identical panel arranged beneath, wherein - the groove-like shape allows the upper extension to move therein. - a first face skin of sheet metal, providing the façade surface of the panel, - a second face skin of sheet metal, providing the back surface of the panel, and - a core arranged between the first face skin and the second face skin, the first and second face skins being attached to the core, - an upper edge, comprising an upper edge skin construed from the sheet metal establishing the first face skin, - a lower edge, comprising a lower edge skin construed from the sheet metal establishing the first face skin, - an upper attachment element arranged in the upper edge, wherein - the upper attachment element comprises a first fixing surface, - the first fixing surface being attached to the second face skin of sheet metal, wherein - the façade surface of the panel is arranged in a first angle in relation to the upper edge skin and the first fixing surface, - the upper attachment element comprises an upper extension for attaching another composite panel above the composite panel, - a lower attachment element is arranged in the lower edge, said lower attachment element comprising - a third fixing surface attached to the second face skin in the lower edge, and - the façade surface of the panel is arranged in a second angle in relation to the lower edge skin and the third fixing surface - said first angle is more than 90°, that - the second angle is less than 90°, and that - the lower attachment element comprises a groove-like counterpart arranged in use to receive the upper extension of an identical panel arranged beneath, wherein - the groove-like shape allows the upper extension to move therein.