Uncle Marvo wrote:
Good point. The only problem then would be a) getting the thing on there in
the first place and b) weeding it. How do the Norwegians, who do lots of
this, manage their weeding? I had assumed that sedum or whatever they use is
short growing stuff which beats the weeds. Maybe not.
Perhaps I'll use astroturf!

That's why I've suggested grass. There's hundreds of examples in the
UK. I see grass roofs everywhere I go. There's even one across the road
from me - though it wasn't intentional ) It just grew over the years
on the ondulated garage roof, it's pecked by birds and is a playground
for baby squirels. A mate did one on his outdoor shower hut. He didn't
bother with different layers, just some butyl and gravel, soil and wild
flower seeds. He has never been up there to weed nor does he bother
with it at all. However he doesn't have asbestos! My hubby told me that
the asbestos could split if you load it too much and then that's when
the dust could become dangerous. (We used to play darts on a door in
our student flat for years until we realised it was asbestos cough).

I've missed my mate last night ... but found her designs in my notes.
I'm putting together her ideas on an email to you.