This is my garden office which I built using part of a kit from Tomoku Hus, a Swedish prefab house manufacturer. The walls came as ready to erect units with triple glazed door and windows already fitted. These wall units are made using wood from sustainable sources, insulated with mineral wool. I designed a roof structure that allowed me to have a ‘living roof’ on one side and a cedar shingle side for harvesting rainwater. I didn’t want the living roof to sit on top of a finished roof but for the roof pitch to be a clean line, so the living roof is recessed. The living roof has a substrate of crushed recycled building waste mixed with some compost to make a low nutrient environment for anything that can, to germinate in. The rainwater run-off from this side of the roof is connected to land drainage perforated pipe which is buried and runs out across the vegetable garden. The outside walls of the building are clad in Western Red Cedar which doesn’t need painting or treating, and it fades to grey with time.