A kit of parts for constructing or reconstructing a roof, wall or façade structure comprising: - one or more retaining elements each having a head section for engaging and holding at least one building sheet of a roof, wall or façade, a base section spaced from the head section, and a connecting member fixedly connecting the head section and the base section, and - one or more supporting rails each comprising a first profile section for detachably receiving and holding the base section of the retaining element and a second profile section, wherein the base section, when positioned in the first profile section is rotatable relative to the supporting rail around the axis perpendicular to the supporting rail between a first position at which the base section is freely detachable from the first profile section of the supporting rail and a second position at which the base section is secured in the first profile section of the supporting rail, the rotation enabling the alignment of the longitudinal axis of the head section of the retaining element with flanged edges of the building sheet, and - one or more mounting elements each comprising a head portion for receiving and holding the second profile section of the supporting rail, a foot portion spaced from the head portion for mounting the mounting element on a roof, wall or façade substructure and a connecting portion connecting the foot portion and the head portion, wherein the supporting rail is rotatable around its longitudinal axis when held by the head portion of the mounting element to enable alignment of the longitudinal axis of the elongate head section of the retaining element with the inclination of the wall, roof or façade. - one or more retaining elements each having a head section for engaging and holding at least one building sheet of a roof, wall or façade, a base section spaced from the head section, and a connecting member fixedly connecting the head section and the base section, and - one or more supporting rails each comprising a first profile section for detachably receiving and holding the base section of the retaining element and a second profile section, wherein the base section, when positioned in the first profile section is rotatable relative to the supporting rail around the axis perpendicular to the supporting rail between a first position at which the base section is freely detachable from the first profile section of the supporting rail and a second position at which the base section is secured in the first profile section of the supporting rail, the rotation enabling the alignment of the longitudinal axis of the head section of the retaining element with flanged edges of the building sheet, and - one or more mounting elements each comprising a head portion for receiving and holding the second profile section of the supporting rail, a foot portion spaced from the head portion for mounting the mounting element on a roof, wall or façade substructure and a connecting portion connecting the foot portion and the head portion, wherein the supporting rail is rotatable around its longitudinal axis when held by the head portion of the mounting element to enable alignment of the longitudinal axis of the elongate head section of the retaining element with the inclination of the wall, roof or façade.