When many people think “green roofing” they visualize plants growing on top of a roof. While this type of roofing can be done and is certainly green, there can be structural support issues which must be dealt with before this type of roof is installed. Think about the sheer weight of all that soil, plant life and water. Your roof isn’t generally set up to bear loads like that without specially installed supports.
A green roofing option that is becoming more and more popular here in the Pacific NW and across the US is metal roofing. Metal roofing materials are considered green for several reasons: 
– They last a very long time without needing replacement and with minimal upkeep.
– Metal is reflective, while asphalt shingles are not. This means that the roof will keep the interior of the house at a cooler temperature during summer by reflecting sunlight instead of absorbing it. This reflective action means the costs of cooling your home are less. The plant material-type green roofs have the same effect. There have been reports of savings up to 25% in annual home energy bills.
– Metal is great at shedding snow when we have a surprise 9″ fall – like we had here in Portland in February of this year.
– Metal roofing materials require very little resources to manufacture – and they can be recycled.
– New metal roofs often contain a high percentage of recycled metal – around 30-60%.
The low environmental impact is what makes metal roofing a green roofing product. The homeowner also gets a great return on investment when it comes to energy bills and on resale value gain over homes with asphalt shingle roofs. So, keep it green!