Turfonline offer a range of products that can be used to create a living roof. But why would you do that? This articles looks at the benefits of a living roof.
What is a living roof?
A living roof is a layer of intentionally planted vegetation on top of a building or a podium. It’s a bit like an enormous plant pot with drainage and a finite layer of growing medium. In other words whatever you plant in it has a limited root run and no access to soil water.
What is the point of a living roof?
Many of the things we need to survive come from plants. Oxygen, air filtration, building materials, non-fossil fuels etc. A higher population, more infrastructure and “better” lifestyles mean less room for the plants we depend upon. Unless we plant things on our roofs. Hence the rise in popularity of living roofs.
In medieval times, a simpler way of life meant that it took roughly 2.5 acres of land to support an adult human. That’s food supply, fuel for heating and cooking, building materials, waste disposal, wool and linen for clothing. Because the population was so low, there was plenty of land to go around.
Modern man has a much more sophisticated lifestyle. He uses transport that is powered by fossil fuels, has several changes of clothing, a home that is heated in winter and cooled in summer. His buildings are made from materials that can never be returned to the earth – and so are many of his clothes. He eats a lot more than his ancestors and instead of catching or harvesting his own food, buys it conveniently packaged from a shop.
He makes liberal use of sewerage and drainage systems, roads, schools, factories, retail units and landfill. It takes a considerable amount of resources to support one modern day adult. And there are considerably more adults to cater for than there were in Roman or Medieval times.
Our ancestors understood the value of living roofs. These are traditional viking houses with roofs made from local materials (turf) that will insulate, cool, and feed the goats. Not many of us keep goats these days but a flowering green roof will certainly benefit pollinating insects.
What are the benefits of a living roof?
Insulation and Cooling
Ever wondered why so many of the world’s wild creatures choose to live in underground burrows? Some of the reason has to be that soil is a great insulator. Even just few centimetres below the surface of the soil the temperature is more constant. Warmer in winter and cooler in summer.
A layer of growing medium on top of a building provides fantastic insulation. For the building’s occupants that means a more comfortable temperature and less dependence on heating and air conditioning. …so it’s a money saver too!
Large scale drainage and sewerage systems are expensive to build and maintain. Some existing systems struggle to cope with the workload of an ever increasing population. So if rainwater could be managed in a different way, our drainage systems would be easier to manage.
A living roof absorbs up to 80% of the rain that falls upon it and then releases it slowly. What that means is, that when a huge volume of rain falls, its progress towards the drainage system is slowed.
A living roof emulates the natural way – when rain is absorbed into the soil and filters down into the bedrock and then to streams and rivers. Instead of streams, water from a living roof could be diverted to a SUDS system or a greywater collection tank for use in flushing toilets or watering plants.
Plants have an amazing way of filtering dust and dirt out of the air before it gets to our lungs. That includes heavy metals and harmful compounds. They also use lots and lots of carbon dioxide. And taking greenhouse gasses out of the air has got to be a good thing – right?
By absorbing some of the nasties, plants are offsetting some of the lifestyle choices that scientists believe are damaging our planet (and indeed our own health). If you travel by car, bus or train, heat your home or cook with fossil fuel, perhaps you should think about balancing those activities by planting live plants wherever you can?
Why do so many trees grow beside roads or railways? They’re not just there to look pretty, and they don’t stay there because nobody can be bothered to cut them down. Those trees and plants are protecting us against pollution and noise.
A living roof insulates against noise pollution from outside a building (roads, planes etc) or from inside (yes, I have lived with teenagers!)
The waterproofing on a roof will not last forever. It is affected by UV light and by changes in temperature and will crack and leak over time. The living roof buildup actually protects the waterproofing and can extend its life 3-fold. That means fewer maintenance bills for you and less damaged waterproofing going to landfill.
Efficiency of PV panels
PV panels are enormously helpful in the fight against high bills and climate change. However, if they are on a roof where the temperature is 30 degrees or more, they become inefficient. The cooling and insulating properties of a living roof keep the temperature down so that you can have the best possible return on investment from your PV panels.
A wild bee enjoying sedum flowers on a living roof
I’ve left this one until last because it’s one of the most important functions of a living roof. When 60% of animals have disappeared since the middle of the last century, it’s time to take action to protect the wildlife we have left.
A well specified and well maintained living roof can provide shelter, resting places and food for a huge number of creatures. Even more important, if there were enough living roofs close enough together, they would create a habitat highway. Meaning that there are no isolated communities of creatures that have no choice but to interbreed. Genetic diversity is just as important to butterflies and beetles as it is to humans and domestic animals. It’s about long term health and the ability to evolve and adapt to changes in the environment.
This green roof cycle shed near Teddington Lock in London was made with Meadowmat Wild Flower Matting.
Make a living roof to help you, your species and your planet
These are just some of the benefits of living roofs. I haven’t included things like aesthetics and design, wellbeing or recreation – we can talk about them another time.
If you’ve been inspired to learn more, you might find these links useful