Large garage - green roof and planting

[TiddleTaddleTat]

We've recently moved into a new house (to us). I'm slowly finding homes for my few plants and planning what to do at the front.
The back garden has an enormous brick built garage that takes up about half its width. We plan to convert this into an occasional space in a few years.

The garage has a flat roof so a friend suggested a green roof might work. Any advice on this or recommended suppliers?

The side of the garage is a south facing wall but has a concrete path down the side. So thinking to have climbers in pots/planters. We don't have much spare cash so I'm after recommendations for climbers that will grow vigorously to conceal the garage and help it blend in, but be happy in a pot.

A good place for cheaper plants is village fetes and or car boot sales. A honeysuckle is good for walls, keep giving it rainwater and feed every month or so (maybe put some hooks either end and string between them first).

Garden centres, Homebase, B&Q begin to sell off plants at the height of summer. They planting rush is over and they don’t want to over winter them.

Sedums and houseleeks (sempervivum) will be happy up there in minimum soil and will pretty much look after themselves. I had one growing on my flat porch roof for years, and I've no idea how it even got up there.