Net Zero Living
Green walls: well beyond ivy-covered facades of yesterday
"Give fools their gold, and knaves their power; let fortune's bubbles rise and fall; who sows a field, or trains a flower, or plants a tree, is more than all."
— John Greenleaf Whittier
One positive outcome of our manic economic situation is that we are forced to look for both simple pleasures and simple solutions in our lives. I personally feel that our ever-increasing green-lifestyle choices are a result of our need to simplify. The zero-energy, low-carbon footprint, and money-saving result of green lifestyles are simply a wonderful and sometimes unexpected outcome.
It is this need for simplicity that I think has also renewed the trend of "green walls." Our lifestyles are more urban-centric than ever before. Green walls can provide the need for beautiful vegetation that humans crave and help to camouflage the noisier and more polluted aspects of urban living. The new green wall is moving past the ivy-covered green facades of yesterday to find a plethora of options with living walls.
The options for living walls fall into three types: loose mediums, mat mediums and structural mediums. The loose mediums are set in a "shelf" system or "soil bag" where the soil is set into the shelf or bag and then stuffed into a hole on the building. These systems will require regular pruning or even replacement as the roots will outgrow the system due to the smaller planting area of the "hole" and the greater possibility of being blown away by high winds and rain.
Another option is the "mat" system that can be either coir fiber or felt pockets. There is a limited lifespan of about three to five years with this system as the roots can become too dense in the fiber to allow proper water penetration. This system does allow the most flexibility as you can hang small or large pockets and the entire planting can be framed to be shown off as the work of art it is. This medium is also good for both interior and exterior applications.
Finally, there is a "structural" type of medium. This is where the plant is set into a "block" and can be manufactured into any shape. This can be the most expensive option, but will also last the longest as it can allow for the most variation of water needs and can be handled more easily for maintenance and replacement.
Green walls also make good use of available vertical surface areas. Not only will this allow for a more beautiful building, but with proper preparation, you will save on the painting and maintenance of the building's exterior. Green walls can also help to reduce the overall temperature of buildings thereby decreasing the amount of energy required to cool them.
The walls can also be a way to reuse water. The plants can absorb the dissolved nutrients and purify slightly polluted water if installed by way of a gray-water system. This point is especially helpful in areas such as the Bay Area where the circulating water on a vertical wall is less likely to evaporate than in traditionally placed gardens.
It is all of these reasons combined that helped Vox Design Group Inc. (a green design/build firm) to decide on a living wall for its new exterior sign on Castro Street. Not only does the runoff from the installed drip system water the native plants at the front of the building, but the wall of succulent-stuffed felt pocket softens the street noise from Castro Street.
It is such a hit with people walking by that they have stopped into Vox's office to simply say how much they enjoy the sign. Thank goodness for the simple pleasures in life.
Forrest Linebarger is CEO and chief designer at VOX Design Group Inc. in Mountain View, and has been designing and building sustainable homes for more than a decade. He can be reached at Forrest@VoxDesignGroup.com or at 650-694-6200, ext. 11.