Climbing plants and especially grapevines are ideal to create green projecting roofs in form of a "gallery." Some examples are illustrated here. This type of façade greening originates from southern countries, where the oven-like temperatures emanating from walls are rather harmful to the espaliered vines. Hence they are trained away from the walls, providing much needed shade at the same time.
For supports, sturdy mountings or wall brackets are required, through which wires or wire ropes can be threaded parallel to the wall. The brackets are available from metalworking shops, and you will need to make sure that their loading capacity is adequate for high fruit yields, windy situations etc.
The interaction of vine and trellis for "gallery greening" occurs as follows: the yearly new shoots first grow upwards, then with increasing weight gradually bend over until they end up lying on the wires, where they get entangled with each other. The images below illustrate some training variations, which can be changed and combined.