Living Roofs AK Townsend

Living roofs are rooftops that are partially or completely covered with vegetation. Once nearly unheard of, living roofs can be found on a growing number of buildings around the world. It has been reported that one-third of all new roofs in 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 the elements. The idea appears to have spread to Scandinavia and, then, to the rest of Europe, where it has gained popularity over the past few decades. Living roofs have several benefits. On hot summer days, they can reduce rooftop temperatures by several degrees, keeping buildings and cities cooler. They also keep buildings warmer in the winter. Living roofs act as air and water filters. They also increase habitat for songbirds and insects and beautify homes and commercial 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 need between one and five inches of soil and support plants with shallow roots. They generally add from 15-50 pounds of weight per square foot onto the roof and do not need any special rooftop construction to support their additional weight. Seeds can be planted by hand or purchased in sheets. These roofs require little to no maintenance. “Intensive” living roofs can support trees and shrubs. Grown in at least one foot of soil, these living roofs can add from 80-150 pounds of weight per square foot to the roof. Building owners will need to ensure that their roofs are strong enough to hold the added weight. These roofs require more maintenance. Living roofs typically are created using several layers of materials. The bottom layer, sloped slightly to prevent pooling, is a waterproof membrane that is laid on the roof to keep moisture in the soil from seeping into the building. A root barrier is added to keep plant roots from digging into the roof. Other layers include special insulation, drainage, and filtration layers. A water storage and irrigation layer helps to ensure that the plants’ roots do not dry out. Finally, soil is added, and vegetation is planted. A wide variety of plant species can be grown on living roofs. Plants that can thrive in strong sun, wind, and drought are good choices. For those who want the benefit of a living roof but cannot spare the space or the expense, partial living roofs are an option. The GreenGrid roof consists of portable, 2-inch-deep containers that can be placed anywhere providing the roof will bear their weight, which can be 15 pounds per square foot when wet. Deeper containers are available as well.

Some of the most advanced and least expensive living roof technology has been developed in Germany. Currently, the Ford Motor Company is constructing the world’s largest living roof on one of its manufacturing plants. It will stretch across 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 Information Germany: Xero Flor - http://www.xeroflor.de/index2.html Optigun - http://www.optigruen.de/2003/start.html UK: Miller Roofscapes - http://www.miller-roofing.com/roofscapes.htm Green Roof Systems Consultancy – http://www.roof-garden-consultancy.co.uk/home.htm USA: GreenGrid - http://www.greengridroofs.com/ http://www.archibio.qc.ca/pages/roof.html