Every now and then I’m given a chicken house to put through some field trials and as a consequence I can end up with quite a few ‘buildings’ covering the field. It was on one such coop I figured I try a different kind of field trial by sticking a green roof on it. Why not, after all it’s a roof like any other so it would provide “the environmental benefits of having a living, breathing space where once there was nothing, transform an otherwise dull space into something aesthetically pleasing AND provide you with more growing space.”
This project will take you through how to go about constructing a simple and effective green roof on your chicken coop. There are options to buy ready-made matting that can be rolled out and attached to a roof but at over £20 a metre this can prove a little prohibitive, especially as this whole project costs less than £20 if you sow or propagate your own plants. Better instead to build your own, that way you can decide the planting plan and over the years it will pad out and provide the same effect as the matting. It also enables you to create your own personal blend of weather-hardy plants such as sedums, alpines, mosses, grasses, seasonal herbs, and house leeks.
In fact you could apply the same design principles to a shed, log store, over even a bird box!
What You Will Need:
- An offcut of pond liner or damp proof liner
- Geotextile membrane or some old blankets
- Sufficient Yorkshire board to go around the perimeter of the roof
- A sack of 10mm gravel
- Peat free compost mixed with sharp sand
Identify a suitable roof structure ideally with a 9-10 degree pitch on it. Check it’s strong enough to take the weight of a saturated green roof and add supporting framework (crossbeams attached to the side supports & roof will help) if necessary.
Attach the section of pond liner or damp proof membrane and make sure it overlaps the edges so water will run off and not seep into the roof. Staple into position and trim off any excess with a knife or pair of scissors
Cut lengths of board to ‘box in’ the roof. This will stop the planting medium from simply washing off. Allow a 5mm gap between the board and the roof on the lower edge. This will help with water drainage.
Staple the geotextile member (or old blanket) to the box sides. This layer will help retain moisture and reduce the need for frequent watering.
Add a 2cm layer of the gravel to the roof. This layer will aid water dispersal and drainage.
Finally add about 5cms of the compost and sharp sand mix and level it out. You are now ready for planting it up.