How to Install a Green Roof

Green roofs, also known as sedum roofs, provide a sustainable solution for creating green outdoor spaces. They also offer improved insulation and effective rainwater management on the roof. Existing buildings can incorporate extensive green roofs with shallow soil and low-maintenance sedum plants without requiring significant structural changes. Installing a DIY green roof is an achievable project for a handy homeowner with proper planning. In this guide, we’ll walk through the key steps of how to install and maintain your green roof oasis.

Step 1: Assess Roof Pitch and Load Capacity

First, check with a structural engineer or building contractor to see if your roof can handle the weight. MobiRoof ECO modular green roof is suitable for flat roofs or slightly sloped roofs up to 10° pitch. Each cassette weighs approx. 38 kg/m2 when dry and 58 kg/m2 when completely saturated. The water capacity of the green roof system is 20 L/m2. To hold more rainwater, add a supplemental buffer layer under the trays to increase water capacity to 40L/m2.

Step 2: Protect Your Roof

Check your roof's material carefully. If your roofing lacks an integrated root barrier, apply a separate root-resistant permeable membrane before installing cassettes.

Step 3: Install Edge Gravel Strips

Install a 300-500mm wide gravel strip (minimum of 16/32 stone) around the roof perimeter and penetrations like skylights and downpipes. Gravel strips around the perimeter and roof protrusions create fire breaks. For fire safety, add additional parapet walls that are at least 300mm tall or 1m wide gravel strips every 40 meters. These perimeter gravel strips also improve microclimate conditions and shield the vegetation cassettes from wind damage.

Step 4: Place the Green Roof Modular Trays

For systems like MobiRoof ECO, modular vegetation trays interlock for simplified installation. For easy mobility across the installed sections, staggering the tray joints offsets seams and working outward from roof access points. You will need 4 cassettes per 1m2 roof space.

Step 5: Maintain Your Green Roof

The final step is routine maintenance. To sustain a healthy green roof, you need to perform maintenance approximately once or twice per year. The maintenance work includes the following tasks:

• Weeding and clearing any unwanted seedlings from the trays.
• Irrigating only during periods of extreme drought to maintain optimal plant balance.
• Pruning strategically in September after bees have finished their life cycle while leaving some cuttings to allow re-growth and habitat.
• Fertilising once or twice annually in spring and autumn to stimulate soil nutrients and plant health.
• Phased pruning of sections over a span of weeks to minimize disruption to resident animal species.

With the right preparation and materials, installing a DIY green roof is an achievable home project. Follow the steps above for green roof success.