World Green Roof Day is a perfect time to highlight the amazing benefits that green roofs bring to our cities and communities. These vibrant, living rooftops are so much more than just a pretty sight – they’re also powerful tools for making our urban environments healthier, more sustainable, and more resilient.
Green roofs are actively working to improve air quality, plants and soil on a green roof act as a natural filter, catching and storing pollutants from the air helping to improve air quality in density populated areas.
They also boost a buildings thermal performance, keeping a building warm in winter and cool in summer, which can significantly lower energy costs, reducing its environmental impact. They can also help to reduce the impact of noise from outside.
Green roofs can also reduce the impact of rain events by absorbing rainwater, slowing down the flow of water, easing the burden on sewer systems and reducing the risk of flooding at ground level. Combined with Blue Roof technology they are an effective method or water attenuation.
Green roofs provide a boost to a city’s biodiversity providing vital habitats for pollinators, like ground nesting bees, birds, invertebrates and other wildlife.
Green roofs not only help the environment but contribute to the sustainability of the building by increasing the lifespan of the roof. The waterproof layer also adds a layer of protection from the sun and rain extending the life of the roof.
It’s amazing to think that something as simple as adding plants to our rooftops could have such far-reaching benefits for our health (both physical and mental), our environment, and our communities – which is why World Green Roof Day is such an important event, as it celebrates these incredible spaces and spread the word about their potential to transform urban areas for the better.
Types of Green Roofs
There are several types of green roofs. It is important in all instances to sought advice from a qualified structural engineer to ensure the roof structure can cope with the additional loading from the substrates used.
1. Brown Roofs
These are roofs which are left for planting to naturally form from wind borne seed and also seeds brought in by birds and other wildlife – generally these are made from an ‘Extensive Substrate’ this is a combination of crushed new brick and Green Waste Compost, our product is known as Boughton’s EX1, it’s important that the crushed brick is a new brick opposed to a reclaimed brick, reclaimed brick could contain contaminants e.g. lead based paints. Extensive substrates can be used with a minimum depth of 80mm up to a max of 200mm.
2. Extensive Green Roofs
Extensive green roof provides a visual or biodiversity interest and generally designed to support plants with a lower maintenance requirement, e.g. sedums, grasses, mosses and some wildflower species. These plants can survive on shallower substrate depths and require lower nutrient levels and little or no irrigation. When correctly designed and installed, irrigation is generally only required in the initial establishment phase and then very rarely afterwards. Shallow substrates can be used.
3. Extensive Wild and Meadow Flower Roofs
Wild and meadow flower roofs are designed to support insect and bird life. Requiring a substrate depth of 100mm – 150+mm, wild and meadow flower plants provide an alternative to low and slow growing sedum planting and is more seasonal in appearance. It is desirable to have watering facilities available at roof level for wild and meadow flower roofs and watering may be required after long dry spells.
4. Biodiverse Roofs
These roofs use a version of the Intensive substrate, but with a different ratio of materials, created to be a lower nutrient content providing the opportunity to grow a range of wildflower species. Roofs using this substrate can also be left unplanted to create a Biodiverse Brown Roof. Biodiverse substrates should ideally be at least 120mm depth to accommodate deep rooting plant material.
5. Intensive Green Roofs
Intensive roofs use a substrate mix which is much richer and is designed for an intensive planting mix, much the same that you would find at ground level, so often large trees, shrubs, perennials climbers and lawns. This can obviously be scaled to small and large applications depending on the scope of the project. Our product for this application is Boughton’s IN1 Intensive Substrate.
For more information, read THE GRO GREEN ROOF CODE
