The Architecture of a Green Roof

Compared with the more traditional roof surfaces, building and maintaining a green roof can be a nightmare. They require a lot of work and a much stronger supporting structure than other kinds; as well, they are well known to be conceptually nerve wracking. But what is a ‘green’ roof ? If you see one, you’ll know. They’re a living roof, that has some manner of green organism growing on it. It’s usually some kind of meadow.

There are several reasons that the conversationalist prefers a green roof and this manner of roof covering has several design elements that place it in that category.

First off, all green roofs have a low construction impact. Modern humans have a bad habit of replacing water-absorbent soil and plants with hard surfaces such as roads, parking lots and even roofs. These cause many different problems like the run off effect from rain water actually raising the temperature in the cities as it runs into the sewers. As well, the places that birds and other animals live are destroyed. On the other hand, a living roof acts like the terrain that it replaced. If you decide to add a patio on a living roof, the new space becomes a place for humans too. Living roofs replace the footprint that is lost, be the existence of the building, and puts it back in on the roof.

From a human standpoint, a living roof is cooler and therefore more economical during the summer months. The layers that are created by this new type of roofing resist many different kinds of heat transfer. Radiant heat, the main source of heat transfer from many roofing systems, is usually absorbed by the plant cover here and not transferred to the building. The wind chill effect (which is the loss of heat through moving air) is also dissipated through the use of a green roof. Remember too that the plants on a green roof create a huge thermal blanket that acts like a buffer zone between the insulation below and the outside.

This type of roof is long lasting as well. The real buffer on any green roof is the water tight membrane that sits under the plants, and the roof will last as long as this membrane. Keep in mind that a well-designed system will protect that membrane from the very forces of nature that attack other kinds of roofing without end. For example, the sun will never hit this membrane and so it will never be bombarded with UV rays. Perhaps most important is the fact that the membrane is protected from freeze and thaw cycles because it’s below layers of the roof.  One of the biggest advantages to this roof is the fact that it’s usually the least toxic part of the house. It’s even possible to grow some kinds of food up there.     

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