A set of parts having fire-shielding properties for assembly of a first and a second wall element into a wall construction, the set of parts comprising: a fire-shielding U-shaped outer frame element adapted for supporting a side of at least one wall element in a wall construction, said outer frame element being elongate and comprising a bottom part and a first side flange and a second side flange, the first and second side flanges extending away from the bottom part, an interior surface of the first side flange being adapted for extending along a first exterior surface of the wall element and an interior surface of the second side flange being adapted for extending along a second exterior surface opposite the first exterior surface of the wall element in a mounted condition of the outer frame element so as to hold the wall element to form said wall construction, wherein the outer frame element comprises a first elongate strip and a plurality of perforations in the bottom part, the first side flange and/or the second side flange, said first strip comprising a material having thermal shielding properties and being arranged on an interior (131, 141) and/or exterior (132, 142) surface of the first side flange and/or second side flange of the outer frame element, wherein the outer frame element being adapted for supporting a side of the first and/or second wall element when in an active mounted condition, characterized in that the set of parts further comprises a fire-shielding fastening means adapted for being arranged between the first and second wall elements, so as to hold the first and second elements together, wherein the fire-shielding fastening means comprises a fastening element comprising: - an elongate base part, - a holding part connected to a first end of the base part, wherein the fastening element is adapted for being arranged in said active mounted condition with - the base part positioned between the first and second wall elements, the holding part extending at an angle to the base part and extending along first exterior surfaces (61, 71) of the first and/or second wall elements, wherein the fastening element further comprises: - a fixation part connected to a second end of the base part, the fixation part comprising a first fixation arm and a second fixation arm, - where the base part and the fixation part extend in the same plane when in an inactive condition, and the fastening element is adapted for being arranged in said active mounted condition with the first and second fixation arms extending at an angle to the base part and extending along a second exterior surface (62, 72) of the first and/or second wall element, so as to hold the first and second wall elements together. a fire-shielding U-shaped outer frame element adapted for supporting a side of at least one wall element in a wall construction, said outer frame element being elongate and comprising a bottom part and a first side flange and a second side flange, the first and second side flanges extending away from the bottom part, an interior surface of the first side flange being adapted for extending along a first exterior surface of the wall element and an interior surface of the second side flange being adapted for extending along a second exterior surface opposite the first exterior surface of the wall element in a mounted condition of the outer frame element so as to hold the wall element to form said wall construction, wherein the outer frame element comprises a first elongate strip and a plurality of perforations in the bottom part, the first side flange and/or the second side flange, said first strip comprising a material having thermal shielding properties and being arranged on an interior (131, 141) and/or exterior (132, 142) surface of the first side flange and/or second side flange of the outer frame element, wherein the outer frame element being adapted for supporting a side of the first and/or second wall element when in an active mounted condition, a fire-shielding fastening means adapted for being arranged between the first and second wall elements, so as to hold the first and second elements together, wherein the fire-shielding fastening means comprises a fastening element comprising: - an elongate base part, - a holding part connected to a first end of the base part, wherein the fastening element is adapted for being arranged in said active mounted condition with - the base part positioned between the first and second wall elements, - an elongate base part, - a holding part connected to a first end of the base part, - the base part positioned between the first and second wall elements, the holding part extending at an angle to the base part and extending along first exterior surfaces (61, 71) of the first and/or second wall elements, wherein the fastening element further comprises: - a fixation part connected to a second end of the base part, the fixation part comprising a first fixation arm and a second fixation arm, - where the base part and the fixation part extend in the same plane when in an inactive condition, and - a fixation part connected to a second end of the base part, the fixation part comprising a first fixation arm and a second fixation arm, - where the base part and the fixation part extend in the same plane when in an inactive condition, and