There’s more and more interest in Green roofs than ever before, as developers and those concerned about the environment explore this age-old method of roofing.
Not least for a green roofs ability to address and overcome certain planning criteria like a West Berkshire school that’s just completed a £60,000 installation. Their green roof making up 80% of the entire roof area – some 6500 square meters.
But it’s not just for getting around planning issues, green roofs provide a number of social and environmental benefits whilst costing the same or sometimes even less than conventional roofs.
A green roof will absorb air pollution including greenhouse gasses and because it’s a living thing, water run-off is also reduced. You end up with a micro-climate effect around your own home.
The materials used to construct a green roof offer protection from UV rays, extra insulation (very handy in the winter but also cooling in the summer) and reduce noise levels. Much of the material used can be recycled building materials and special composts are used to promote quick growth of the vegetation whilst being lighter than ordinary soil and more suited to water retention/run off.
So when you invest in a green roof, you’re also saving the amount of material that traditionally would have gone to landfill.
Basic construction of green roofs involves several layers, each with their own part to play. Starting with the structural layer at the bottom (which must be able to take the weight of the covering when its wet / additional snow layers on top), several layers of membranes are applied to insulate, stop roots growing through and provide drainage and aeration etc. before the final ‘soil’ layer is applied which can then be planted.
The only decision to make is what you’re going to plant on your roof – beware as some mixtures of recommended plants can be more labour intensive than other combinations. It all depends how much time you want to spend on your roof.
The school project I mentioned earlier involved the planting of 68,000 small plants, chosen by the pupils as part of their curriculum studies. They chose their plants to provide as much variation of leaf colour, foliage, flower colour and height as possible, to make it an attractive environment whilst also providing a very bio-diverse environment for wildlife.
Their involvement didn’t stop at just choosing the plants – many pupils were involved in the actual planting operation to.
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photo credit: d sharon pruitt