Make a green roof on a shed

Lay the water-impermeable sheeting over the roof, cutting it to size with a slight overhang. Fasten to the side of the shed using a hammer and tacks.

Saw four lengths of timber to match the dimensions of your roof. Screw them to the sides of the shed. Drill drainage holes (2cm) at the lower end.

Put a small block of wood in each corner, screwing through the frame to secure them. This adds strength to the structure.

Pour a layer of gravel into the frame, 2–3cm deep. This improves the drainage of the green roof, which helps reduce soil erosion and aerate plants.

Cut a piece of weed matting large enough to cover the roof and the inside of the frame. Lay it over the gravel and attach to the frame using tacks.

If you’re worried that soil may be too heavy, place potted plants on the gravel instead and surround them with woodchip to reduce weight on the roof.