A good example of the before and after effects of laying a sedum roof garden and accompanying deck and paved area onto a small domestic roof terrace.
As all these products are designed to sit on top of the waterproof membrane (in this case single ply) there was no issue of damage to the roof.
The support pads lifted the decking off the roof, eliminating the risk of the timber piercing the membrane, and drainage was maintained through the roof surface since the green roof system has a cavity beneath its own reservoir and drainage layer to allow water run-off.