This is a project I completed back in October, secure cycle storage and a green roof. The client wanted secure storage in the front garden without having a big ugly box taking up all the space for planting and we came up with this elegant solution.
As the shed is on the way into the house we planted a number of different herbs which can be easily picked when you are on the way home and also release a scent if you brush past. These were combined with some flowering plants (it was October so not much available) and sedums. The whole roof was also sown with wildflower seeds so should be quite productive in the spring. There are saffron crocus bulbs underneath which may start to appear in late summer.
The bike shed itself has capacity for 2 bikes but there is a larger 4 bike version or these can be put side by side for multiples https://www.asgardsss.co.uk/twin-bike-locker.
This type of roof can be more easily accessed by the householder so we can try and create a slightly more formal garden than I would on a normal green roof as you can change the plants around and water and feed them if it is necessary.
The green roof itself has a fleece at the bottom then a drainage layer of aerated clay pebbles before the soil, here to about 125mm depth but the sheds are pretty tough so this could be bigger if required. The sleepers look really good but an alternative would be cobbles in gabion cages depending on what would fit with your front garden. Order page.