Jun 21 2016

What Are Green Roofs?

Green roofs are a type of vegetated roofs, which were very common in Scandinavia.  Their appeal is very attractive and they have numerous benefits.  They are currently becoming more and more popular and many people opt for this roof style when they build eco friendly houses.

Here are some facts on green roofs:

  • Green roofs consist of vegetation, a growing medium and a waterproof membrane.  Some roofers specialize in the construction of green or “living” roofs.  Sometimes plants are kept in containers, although some people do not consider those true green roofs.
  • They act as superb insulation.  The roof keeps the house cooler in the summer and warmer throughout the winter.  Your bills will be lower and this also means your HVAC and heating equipment will last longer.  There is also significant noise reduction compared to conventional roofs.
  • The vegetation does not need maintenance (such as mowing)!  Alpine grasses, wildflowers and succulents are all excellent choices.  You want to make sure the plants are suitable for the climate but do not require any special care. Some people like pollinator blends to attract hummingbirds, bees and butterflies.  They are planted in nutrient rich growing media which drains very quickly, to prevent standing water and too much weight accumulation.
  • It reduces stormwater run off.  The plants and media slow down the flow of water, which controls urban runoff.  The plants also help evaporate the water instead of simply sending it to the drain.  Some test indicate that, in the summer months, 50% of the water is being witheld by green roofs.
  • ButterflyBringBackNatureIt helps the local wildlife.  It creates a small sanctuary for pollinators, bugs, birds etcetera which is beneficial for the local ecosystem and sustainability.
  • It is aesthetically pleasing.  Seeing vegetation and greenery makes people happier and more at ease.  Green roofs fit that picture perfectly.
  • When greening a roof, you can extend the lifespan of the waterproofing membrane by 200% because the vegetation protects the membrane from UV rays.
  • Green roofs will help reduce air pollutants, as well as greenhouse gases.
  • Better fire protection.  They are less likely to catch on fire and do not burn as hot as conventional roofs do.
  • One of the disadvantages is the weight.  The structural framing has to be engineered to hold the additional weight of the green roof.  Initial installation cost also can be quite higher than traditional roofing.  Since the roof will attract certain insects, you will have to use screen in your windows or you will be letting bugs in.

 

Green roofs are a beautiful, sustainable and eco friendly way to roof your structure.  It has its pros and cons but we hope you enjoy it as much as we do.  If you’re not quite ready to outfit your house with it, perhaps try it on your garage roof first!

 

Written by Sander Vanacker for Bring Back Nature Inc – a Benefit Corporation

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