A method of installing a window arrangement comprising a number of neighbouring windows (231, 232, 233, 234, 235, and 236), comprising the steps of i) providing a support structure, ii) providing a first gable element of a set of gable elements, iii) mounting the first gable element on the support structure, iv) providing a second gable element of said set, v) connecting the second gable element temporarily and releasably to the support structure at a distance from the first gable element corresponding substantially to the width of a window, vi) providing a first window of a first set of opposed windows with a plurality of predefined connection points, vii) connecting the first window with the first and second gable elements (221, 222) and with the support structure, viii) providing a second window of said first set of opposed windows with a plurality of predefined connection points corresponding to predefined connection points of said first window, ix) placing said second window next to said first window, x) connecting said first window with said second window at corresponding predefined connection points. xi) releasing the second gable element from the first window and from the support structure, xii) connecting the second gable element temporarily and releasably to the support structure at a distance from the first set of opposed windows corresponding substantially to the width of a window, whereby steps vi) to xii) are repeated a number of times corresponding to the predefined number of sets of opposed windows, except for step xiii) wherein the second gable element is connected permanently to the windows of the last set, the method further comprising the step of: xiii) connecting the windows of neighbouring sets of opposed window to each other in connection points, xiv) connecting the windows of the first set of opposed windows to the first gable element in connection points and connecting the windows of the last set of opposed windows to the second gable element in connection points. i) providing a support structure, ii) providing a first gable element of a set of gable elements, iii) mounting the first gable element on the support structure, iv) providing a second gable element of said set, v) connecting the second gable element temporarily and releasably to the support structure at a distance from the first gable element corresponding substantially to the width of a window, vi) providing a first window of a first set of opposed windows with a plurality of predefined connection points, vii) connecting the first window with the first and second gable elements (221, 222) and with the support structure, viii) providing a second window of said first set of opposed windows with a plurality of predefined connection points corresponding to predefined connection points of said first window, ix) placing said second window next to said first window, x) connecting said first window with said second window at corresponding predefined connection points. xi) releasing the second gable element from the first window and from the support structure, xii) connecting the second gable element temporarily and releasably to the support structure at a distance from the first set of opposed windows corresponding substantially to the width of a window, whereby steps vi) to xii) are repeated a number of times corresponding to the predefined number of sets of opposed windows, except for step xiii) wherein the second gable element is connected permanently to the windows of the last set, the method further comprising the step of: xiii) connecting the windows of neighbouring sets of opposed window to each other in connection points, xiv) connecting the windows of the first set of opposed windows to the first gable element in connection points and connecting the windows of the last set of opposed windows to the second gable element in connection points. xiii) connecting the windows of neighbouring sets of opposed window to each other in connection points, xiv) connecting the windows of the first set of opposed windows to the first gable element in connection points and connecting the windows of the last set of opposed windows to the second gable element in connection points.