A while back I started to try and cover a small shed in my garden with a green roof - they are meant to be great for insulation and personally I think they look great.
Sadly this first photo is not my shed - but a great pic from an excellent slide show by Grist - see it here with a roof that also has vegetables growing on it!
The next series of photos though is me at work in the garden. First up the solid timbers - all from a local skip (with owners permission) - about 5 inches high edge around using a corner bit of lathe to fix - hey you can tell I'm not a carpenter - then a liner - it needs to be something that can cope with some moisture - next up the butyl pond liner.
Then depending on the angle of the roof you will need gravel - I had a couple of centimetres depth - then a layer of weed suppressant material - this lets water through but not the soil. Then I needed to make a good waterproof fix with the wall - used flashing tape that you peel off the back and it sticks wonderfully - in a few places used some gutter sealant stuff that I had left over from a previous job.
I did also add a hole in the roof for the water to go into a water butt - it is working OK but I will need to make some adjustments - basically rain goes through the soil and membrane into the gravel then filters it's way to the corner where it goes down the pipe - see photo.
Next up the growing medium went in - organic soil conditioner and compost with lots of vermiculite. Then a wildflower mix without the deep-rooted stuff and hey presto...had thought about sedums like the photo below but they take a time from seed and are expensive to buy - not sure about adding grass next year or trying something else?
There are many sources of info on the net - this pic left was one I took at the CAT centre in Wales where they describe one of their green roofs.
Some useful design websites I found include:
Green Roof Forum
Green Roof Centre
Grass Roof Company
In other countries green roofs are much more common - I hope they take off more here as I think they look great - it has certainly softened the look of our shed.