Last Updated on February 15, 2022 by Real Men Sow
Green roofs on sheds are a popular way to fight climate change and biodiversity loss. A green roof shed has become a symbol of beauty and elegance, turning angular buildings into beautiful structures. These kinds of roofs bring birds, butterflies, and bees color and movement to green roofs. They filter air pollutants, slow down rainwater runoff in downpours, and reduce flood risk.
A green roof shed can be a striking feature on a large scale. With a little planning, they can also be a great way to grow more food. If you have an outbuilding, shed, or wood store that has a bare roof and needs to be renovated, it might be worth considering.
Planning a Green Roof Shed
Green roofs typically have several layers. These include a waterproof/root barrier to protect the roof, drainage, water retention mat and then the growing medium and vegetation.
Perfect Metrics For Roof Sheds
These layers can be more than 100 kg/square meter or 20lbs/square foot when saturated. This weight will likely be too heavy for your garden shed. So, consider whether additional support may be needed. To support the extra load, a roof frame may be necessary.
To prevent the growing medium from slipping or sliding in wet weather, roofs with pitches greater than 20 degrees should be divided into several boxes or compartments. Green roofs are not recommended for slopes higher than 30 degrees.
What’s the cheapest green roof?
A carpet of sedums is the simplest and most cost-effective green roof option. These tough succulents can withstand both drought and deluge and are loved by butterflies and bees for their beautiful blooms. Wildflowers are a step above sedums in size and cost. They include alpine plants, native plants, and bulbs.
Why Should You Build Roofs?
Roofs with easy access are ideal for growing hardy herbs like thyme and prostrate rosemary. An edible green roof can also be used to grow small-rooted crops like strawberries and salad leaves, but these should only be grown in the most accessible parts of the roof.
Green Roof Construction
To hold green roofs of herbs and creeping plants in place, a frame needs to be placed around the perimeter. This frame can be made from timber or off-the-shelf metal.
The waterproof/root barrier layer is first because this will protect the roof’s surface from water damage and leaks. Butyl pond liner, or builder’s resin is an option for small-scale roof repairs. If you are unable to use a single piece, make sure to seal all edges because this waterproofing layer can be attached directly to the roof. However, it should not puncture. You can also wrap plywood with waterproofing material and secure it to the roof.
How to layer a green roof?
A layer of drainage is required for larger roofs. This layer is typically a honeycomb-shaped, purpose-sold plastic honeycomb material. This layer is not necessary for smaller green roofs such as those in the photos. The filter sheet will hold the growing medium in its place. It will prevent finer particles from clogging the drainage layer.
A sedum roof should have a minimum of 8cm (3in) depth, and a wildflower, herb, salad, or strawberry roof, a minimum of 15cm (6in). Multipurpose soil-less, non-peat-based potting mix is good for herbs and other edibles. However, you should add plenty of perlites to improve drainage and reduce weight. A very poor, low-nutrient growing medium is required for wildflowers and sedums. This is possible with equal amounts of expanded clay granules, potting mix, and potting mixture.
Planting a Green Roof On Sheds
It’s finally time to plant the plants. Although ready-to-roll sedum carpets are the easiest, you can also find plug trays and other plants that are specifically designed for green roofs. It will be even cheaper to take cuttings or sow seed to grow and transplant. It is best to use a variety of plants across the roof. Mixing different species makes the community more resilient and interesting.
Watering plants for the first year after they are planted is important to ensure proper establishment. In hot weather, salads and herbs with limp leaves may require frequent watering. The plants at the roof’s apex will dry faster than those farther down. Replanting mature green roofs with bare patches will be necessary. It is worth spending the time and money to set up a green roofing system. It’s an amazing thing once it’s fully populated.