Putting down roots with living walls and roofs

Karen Lawson | Improvement Center Columnist | April 24, 2013

Owning a home has traditionally been about putting down roots, figuratively, but also literally. Think of a child's drawing of a house; there are usually a few flowers or a tree in the foreground. But a tree on the roof?

Why not? Living roofs are sprouting up in cities and towns everywhere, and--hold on to your planters--so are living walls!

Living roofs: from ancient Babylon to suburbia

Living roofs are nothing new. Techniques for growing roofs were used to construct the famous Hanging Gardens of Babylon; and using living plant material for roofing has taken root in many cultures. Early living roofs usually consisted of sod braced by a framework of timber. In Iceland's extreme climate homeowners have used sod roofs for insulating their homes for hundreds of years. European farmers and homeowners have roofed homes and barns with sod since the Middle Ages.

In that same time-honored tradition, today's living roofs are durable, sustainable and benefit the environment as well as homeowners.

What's growing on up there?

Living roofs are typically constructed by growing a variety of plants rooted in panels of polypropylene mesh. At minimum a living roof also includes growing medium, an insulation layer, drainage system and a waterproofing layer between the living roof and the roof deck.

Panels of plants used for constructing a living roof contain a mixture of plants suitable to your area's climate and your home's light exposure. Incorporating a variety of plants within a living roof achieves biodiversity and prevents your roof from being destroyed by pests or diseases that prey on a specific type of plant. You can select planting schemes for your roof that reflect your home's architecture, locale and your color preferences.

Living roofs can be installed in any area where they are allowed by zoning laws and building authorities. Before embarking on your living roof project, discuss building code compliance and zoning issues with your county building inspector and prospective contractors.

Green power: living roof benefits

Greenroofs, as living roofs are sometimes called, originally provided protection from the elements in areas where roofing materials were limited. What are the advantages of installing a living roof today?

  • Plants are sustainable and readily available.
  • Planting a living roof reduces environmental impact of using non-sustainable roofing materials.
  • Living roofs usually last longer than traditional roofs.
  • Plants used in living roofs reduce heat outdoors and indoors.
  • A living roof typically reduces energy costs by 25 to 50 percent in the hottest months of the year.

A sustainable investment

Living roofs generally cost more than traditional roofs, but the initial cost is offset by long-term benefits. Greenroofs.com, a media portal for the greenroof industry notes that "[t]he initial extra short-term capital costs of greenroof construction can be offset through long-term maintenance and energy savings."

The Environmental Protection Agency (EPA) estimates that living roofs cost about $10 to $25 per square foot to install.

Living walls: creating botanical art

Living walls, or vertical gardens, are easy to install and small installations work well for limited spaces. You can buy a living wall system measuring 32"-by-24"-by-2" deep for about $120 minus the plants but including root wrappers and drip lines. What are the benefits of a vertical garden?

  • Indoor plants help with removing undesirable organic compounds and improving indoor air quality.
  • A living wall installation saves space on tables, shelves and household surfaces.
  • It keeps plants out of the way of children and pets.
  • A vertical garden provides a decorative focal point indoors or out -- not to mention, a great conversation starter.

Vertical garden systems consist of one or more plastic panels that support a planting system of individual compartments into which plants are placed in a root wrapper and surrounded by soil. Compartments are typically constructed of a fabric made from recycled plastic bottles. You can buy living wall systems that include drip lines or that are designed to be hand-watered.

Like choosing any household plants, you should select those for a vertical garden according to their light and care requirements. Be creative in your choice of plants, as a living wall should be a startling but pleasant visual experience. Modular living wall systems allow you to move plants within the system if you want to rearrange them. Nurseries and home improvement stores often carry living wall systems and can also help with plant selection.

As a homeowner you may already feel firmly planted in your neighborhood, town, city or part of the country, but adding an Earth-friendly living roof or vertical garden to your home might just be a way to feel more rooted to the planet.

About the Author

Karen Lawson is a freelance writer who enjoys writing about home improvement and gardening. She earned B.A. and M.A. degrees in English from the University of Nevada Reno. Karen lives near Reno, Nevada and is usually working on home and gardening projects with "help" from her four dogs.