Description:
I built this 'mini-GR' for a client (I'm a garden designer & one-man landscaper : www.ba-gardendesign.com). As you can see it's on a log-store.

Elements:

Waterproof Layer

I used a piece of plyboard covered with some reclaimed polythene sheet (this was folded up at the sides to contain all other layers & substrate).

Moisture Retention Mat

This sat on top of the waterproof layer. It was felt a drainage layer was unnecessary given the slope angle and small size of the roof. Also, as no-one is likely to be walking over it so extra protective layers were redundant.

Growing Medium

The growing medium was a mix of 10% vermiculite, 10%, grit and 80% coarse-textured peat-free compost. This may prove a bit rich but only time will tell. The total growing medium layer approximately 50mm.

Planting

Plants included Festuca glauca, Geranium cinereum, Pulsatilla vulgaris, Thymus, Saxifraga arendsii, Cerastium tomentosum (this may need a little controlling - but this roof is easily accessed!)

There is a fair amount of shade from neighbouring sycamores, so I've opted for plants I hope will put up with this as well as the wind and rain (the garden looks up toward Snake Pass). Aspect is N-facing, too, which lowers available light.

Other Features

The drain at the bottom was simply a space between the base & retaining edge covered with 20mm gravel that had been reclaimed from some resurfacing work on the property.

The horse-shoes were found close by in the garden. The wood-store is sited next to a stable building (no longer housing horses).

Aspect:
N-facing, too

Location:
Glossop, Derbshire