Living Roofs

Studies have shown that green roofs can reduce heating and cooling costs by 25 to 50 percent. Plus, an eco-roof can last some 50 years longer than a conventional roof.

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Filed under: Eco-Friendly, Succulents

Are you looking for a way to make your home greener? Consider an eco-roof.

An eco-roof, or living roof, is a vegetative roof system that is comprised of several layers: a waterproofing membrane, a root barrier, a drainage layer, filter fabric, soil and plants. The root barrier — something like a pond liner — prevents roots from penetrating the waterproofing material. A drainage layer draws excess moisture, and a filter layer prevents soil from clogging the drainage system. Then the soil is set in place, and the plants are planted.

Benefits of an Eco-Roof
Studies have shown that green roofs can reduce heating and cooling costs by 25 percent to 50 percent. Plus, an eco-roof can last some 50 years longer than a conventional roof.

Just like your ground-level landscape, the viability of an eco-roof depends on the climate, sun exposure, soil and plant type and maintenance. So you can grow anything from succulents to vegetables — as long as you provide the plants with everything they need to grow successfully, especially sun exposure and water.

Extensive vs. Intensive Eco-Roofs
Eco-roofs can be either extensive or intensive:

An extensive roof can have a pitch as steep as 45 degrees, with a soil depth ranging from two to five inches and the plants ranging from two to six inches tall. Extensive roofs requires minimal to no maintenance, as plant choices are easy growers like succulents, flowering herbs and grasses.

Intensive living roofs can handle more weight. For example, big building rooftops are generally flat and can contain trees, planter boxes, gardens and, in some cases, ponds. Clearly these are larger scale and have greater maintenance requirements.

Structural Considerations
What do you do if the structure wasn't built specifically for a rooftop garden? With any existing buildings like your home or your garden shed, you'll want to have an engineer evaluate the building and determine if the building can sustain the load. Look on the membership directory of green-building associations when finding a qualified contractor or engineer. Every city has its own requirements in terms of code compliance and building permits. Consult with the appropriate professionals to make sure your eco-roof installation is handled the correct way.

You can design your eco-roof to have its own drainage system for water runoff. Here, the filtration layer on top works to filter toxins and pollutants from rainwater. The roof is designed so that the excess water runoff comes down one downspout. The water then is directed to an overflow irrigation system well where it can be used to irrigate plants in your garden.