Posted: 22/08/2016 at 19:00
A thick enough layer of gravel should prevent grass coming through. You might need to experiment a bit with putting membrane down. I think that could be tricky.
I see what you mean about the sand - that's fair enough. The really gritty stuff would be best - the kind they lay paving onto without mortaring. How about just putting it down on the soil instead of bothering with membrane at all? That may be the best option. Blocking the light thoroughly will prevent grass coming through
Paving blocks will be ideal for your edging.
A lot depends on the size of the space and the slope if there is one. If everything's well contained and firmed down, it should be fine