Often happens that the window opening is not always perfect. The window is attached to the walls of the opening using mounting plates. Then the space between the frame and the walls of the window opening is covered with mounting foam. In addition, it is necessary to set the window so that the lower edge of the window is higher than the drain, otherwise the wood is possible. After that, it is necessary to install the windowsill, which should go a little under the window. The gap between the windowsill and the window opening is also covered with mounting foam.