Living Roofs AK TownsendLiving roofs are rooftops that are partially or completely covered with vegetation.Once nearly unheard of, living roofs can be found on a growing number ofbuildings around the world. It has been reported that one-third of all new roofsin some parts of Europe are living roofs.The history of the living roof can be traced back a few hundred years to Iceland,where buildings were topped with sod for insulation and protection from theelements. The idea appears to have spread to Scandinavia and, then, to the restof Europe, where it has gained popularity over the past few decades.Living roofs have several benefits. On hot summer days, they can reduce rooftoptemperatures by several degrees, keeping buildings and cities cooler. They alsokeep buildings warmer in the winter. Living roofs act as air and water filters.They also increase habitat for songbirds and insects and beautify homes andcommercial buildings. Living rooftop gardens can be created for a peaceful, cool,park-like atmosphere above the noise and busyness of the city below.Living roofs can be divided into two categories. “Extensive” living roofs needbetween one and five inches of soil and support plants with shallow roots. Theygenerally add from 15-50 pounds of weight per square foot onto the roof and donot need any special rooftop construction to support their additional weight.Seeds can be planted by hand or purchased in sheets. These roofs require little tono maintenance.“Intensive” living roofs can support trees and shrubs. Grown in at least one footof soil, these living roofs can add from 80-150 pounds of weight per square footto the roof. Building owners will need to ensure that their roofs are strongenough to hold the added weight. These roofs require more maintenance.Living roofs typically are created using several layers of materials. The bottomlayer, sloped slightly to prevent pooling, is a waterproof membrane that is laid onthe roof to keep moisture in the soil from seeping into the building. A rootbarrier is added to keep plant roots from digging into the roof. Other layersinclude special insulation, drainage, and filtration layers. A water storage andirrigation layer helps to ensure that the plants’ roots do not dry out. Finally, soilis added, and vegetation is planted. A wide variety of plant species can be grownon living roofs. Plants that can thrive in strong sun, wind, and drought are goodchoices.For those who want the benefit of a living roof but cannot spare the space or theexpense, partial living roofs are an option. The GreenGrid roof consists ofportable, 2-inch-deep containers that can be placed anywhere providing the roofwill bear their weight, which can be 15 pounds per square foot when wet. Deepercontainers are available as well.
Some of the most advanced and least expensive living roof technology has beendeveloped in Germany. Currently, the Ford Motor Company is constructing theworld’s largest living roof on one of its manufacturing plants. It will stretchacross 10.4 acres of rooftop.If you are interested in constructing a partial or full living roof on your home,hotel, or office building, you can contact the companies below for information,supplies, and installation.For Additional InformationGermany: Xero Flor - http://www.xeroflor.de/index2.htmlOptigun - http://www.optigruen.de/2003/start.htmlUK: Miller Roofscapes - http://www.miller-roofing.com/roofscapes.htmGreen Roof Systems Consultancy – http://www.roof-garden-consultancy.co.uk/home.htmUSA: GreenGrid - http://www.greengridroofs.com/http://www.archibio.qc.ca/pages/roof.html