Hi folks,
If anyone is considering a living roof, I've posted a video outlining the construction of ours and how it's fared over the last 4 years of growth. It was done on a budget, using mainly sedums and other succulents which were all propagated from around 100 original donor plants, then planted out into pumice/potting mix, which itself was placed onto the roof in hessian sandbags in order to retain the soil whilst the plants established over the first few months.
Long story short, we've been really pleased with how it looks and performs, providing insulation and protection from the weather. It was also relatively easy to install (just time consuming), and very easy to maintain (just some occasional weeding of the most prominent weeds.
Any questions, feedback or suggestions, please feel free to fire away!