This green roof on an extension in Welwyn Garden City is nearly 10 years old and has been thriving. This was the first green roof I made so I was a little cautious about the loading, the middle are is sedum on a foam drainage mat with very little soil. The edges have more soil and substrate so they are able to support wildflowers, grasses and self seeded local plants. Nowadays I would add a lot more substrate but it is still going strong and the recent rain and sunshine combination has got it growing beautifully.
The sedums are quite persistent and even managed to self seed and create a little patch of growth on the gravel driveway which looks great and offsets the potted plants.
This one was retrofitted which encourages caution, you don’t want the roof to fall down but you can find a combination of plants and sedums that will work on almost any flat or gently sloping roof. Even better if you are building a new extension you can specify the roof to take any depth of soil you want for a really fabulous roof with the plants of your dreams. Drop me a line if you want to know more firstname.lastname@example.org