What color is your roof?

We’ve blogged about the benefits of white roofs, the reflective coatings purported to provide energy-saving benefits in specific climates. But is a “green roof” really green?

Green roofs have been a part of life in Europe and Asia for many years, similar to sod or garden roofs. Composed of earth and living plants, a green roof provides a cooler roof during the summer months than a traditional roof, thereby reducing the energy required for cooling. Additionally, the earthen roof will soak up precipitation, thereby reducing the quantity of rainfall going into storm sewers or streets. And no, a “green roof”  is not always green – due to changes of season, green roofs may appear red, orange, yellow and all colors in between at different times of the year.

Green roofs are just beginning to become a trend in the United States, but the implementation is not as simple as it may sound.  Green roof technology requires significant training and knowledge regarding plant biology, hydraulic engineering and architecture. Green roofs are the result of a complete underlying roof build-up system, providing continuous, uninterrupted layers of protection and drainage. Calculations of load bearing weight can be limiting factors in the design, as a structural engineer will need to assess roof loading capacity and maximum loading conditions.

Basically, green roofs are vegetated roof covers, with growing media and plants taking the place of bare membrane, gravel ballast, shingles or tiles. The number of layers and the layer placement vary for each individual project, but at minimum all green roofs include a single to multi-ply waterproofing layer, drainage, growing media and the plants, covering the entire roof deck surface.  Green roofs have two distinct types of design, termed extensive and intensive, but may also include features of both and then are referred to as either semi-extensive or semi-intensive.

Typical costs for the technology is quite varied contingent on the type of green roof chosen, commonly ranging from $14 a square foot to upwards of $40 a square foot. There are several websites that provide extensive information on the concept and design of green roofs, such as www.greenroofs.org and www.greenroofs.com so for detailed information we recommend your visit these specialists.

Readers, if you have any experience with this type of roof please share your thoughts with us by leaving a comment!

Cindy Conservation, Green Communitites, Green Living earthen roof, energy conservation, garden roof, going green, green roof