yeah, my brother for an a-level cdt project put a load of boards on the house with bolt ons.
fixed vertical wooden brackets to the wall (drilled into brick is crucial). then put ply pannels on them.
trouble with this is that when the weather was good enough to use it we wanted to be out at the crag, the boards were therefor removed by the old man and used as spot boards for cement mixing.
insted, we are building 45 degree and a 30 degree boards inside the garage in the summer.
(get to know a builder, they can get you much cheepness down the merchants :D )