NOVELTY - Mounting a solar module (1) on an aluminum containing support structure involves: i) providing a solar module comprising a top part (40) having top layer (11) and solar cell layer (12), and a bottom part (41) comprising multi-layer backsheet (13) having bonding layer, where bonding layer comprises a polyolefin sheet containing cross-linked polymer selected from polyethene homo polymers, polypropene homopolymers, polyethene copolymers derived from ethene and alpha -olefinic hydrocarbons; and ii) laminating bonding layer to support structure.    USE - For mounting a solar module on an aluminum containing support structure (claimed).    ADVANTAGE - The backing layer protects the solar module from environmental deterioration and provides electrical insulation. The backsheets containing the exposed polyolefin sheets provides the mechanical stability, weathering (yellowing) resistance and/or electrical insulation required for backsheets in solar modules. Surprisingly, the multi-layer backsheets are more resistant to exposure to humid heat than multi-layered materials containing no polyolefin sheets. The polyolefin-sheet allows for the good lamination of the backsheet to aluminum containing support structures.    DETAILED DESCRIPTION - Mounting a solar module (1) on an aluminum containing support structure involves: i) providing a solar module comprising in order of position from the front, i.e. the light-receiving side, to the back: (a) a top part (40) comprising a top layer (11) and a solar cell layer (12) and (b) a bottom part (41) comprising a multi-layer backsheet (13) having at least one bonding layer where the backsheet has a top surface contacting the solar cell layer, which preferably is fully encapsulated, and opposite to it a rear surface exposed to the outside of the solar module, where the bonding layer forms at least a part of the rear surface and comprises a polyolefin sheet containing as its major component a cross-linked polymer selected from polyethene homo polymers, polypropene homopolymers, polyethene copolymers comprising repeating units derived from ethene and at least one alpha -olefinic hydrocarbons, polypropene copolymers comprising repeating units derived from propene and/or at least one alpha -olefinic hydrocarbons; and ii) laminating the bonding layer to the support structure. INDEPENDENT CLAIMS are included for the following:    (1) an aluminum containing support structure for solar modules comprising a solar module laminated to the support structure by the bonding layer of the backsheet; and    (2) a solar module comprising in order of position from the front, i.e. the light-receiving side, to the back: (a) a top part comprising a top layer and a solar cell layer, and a bottom part comprising a multi-layer backsheet having at least one bonding layer where the backsheet has a top surface contacting the solar cell layer and opposite to it a rear surface exposed to the outside of the solar module, where the bonding layer forms at least a part of the rear surface and comprises a polyolefin sheet containing as its major component a cross-linked polymer selected from polyethene homo polymers, polypropene homopolymers, polyethene copolymers comprising repeating units derived from ethene and at least one alpha -olefinic hydrocarbons, polypropene copolymers comprising repeating units derived from propene and/or at least one alpha -olefinic hydrocarbons; where the bonding layer has a length (L') that is greater than the length (L) of the top part and can be folded around an edge of the top part of the solar module.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a photovoltaic module.    Solar module (1)    Top layer (11)    Solar cell layer (12)    Multi-layer backsheet (13)    Top part (40)    Bottom part (41)    Front side (110)    Rear surface (111)    Polymeric material (121)    Solar cell (122)    Electrical wirings (123)