03/08/2023
Green roofs have become increasingly popular in the last 20 years, with their technology advancing from where it began 40 years ago.
Most people are unaware that there are two types of green roof.
One is the ‘Green Roof’ consisting of a sheet or substrate that sedums live on and in so that the roots lock into the substrate. These are grown on a nursery or farm. The material sheet is rolled out and cut to shape on the roof. These plants require little water, are varied in species attracting bees insects and butterflies to pollinate the flowers. This means that what was a sterile roof structure, normally flat or gently raked, becomes a viable part of biodiversity giving back to the environment.
The other green roof type is the living roof; structurally stronger and taking the weight of soil, plants, even rocks and paving slabs to make a roof garden, which can be planted with grasses as well as sedum species .
Both roofs do something special, not only cooling the building and protecting the roofing materials and inhabitants from harmful Ultra-violet rays but also attenuating and filtering water. This means that rainwater is held back in the soil and plants temporarily, reducing the overflow of rainwater into our public sewers. Planners and building control like this and the part it plays in sustainable building design.
The quality of the water is soft (not containing calcium which creates limescale deposits) and is so good, it is ideal for flushing toilets and even using in washing machines. In some instances with further filtration the water could be used for sink taps, washing up and utility rooms. It is a great way to reduce your environmental cost and impact further reducing the average personal water consumption of 14 litres per day.
These roofs once installed require little maintenance with only a little extra watering on very hot summer days, and the removal of tree saplings yearly from bird droppings and wind blown seeds. Green or Living Roofs are a significant asset to any home helping to gain planning agreements from sustainable building design.