BRING YOUR ROOF TO LIFE

Green roofs have been around since at least the time of the Vikings, who laid birch bark and sod on top of boards to keep drafts out of their homes.

- KARUNA EBERL

The modern incarnation of these roofs began in 1960s Europe. Now they are sprouting up everywhere, thanks to their aesthetics, sustainability and long-term cost savings. Is a green roof, also called a living roof, right for you?

"Germany started looking at green roofs as a way to cut down on the spread of wildfires," says Jim Mumford, president and resident horticulturist at Good Earth Plant Company in San Diego. "And then it came across the Atlantic."

Today, Europe is still the leader in green roofs. But several U.S. cities are embracing the benefits and giving incentives to homeowners to install them. New York, Portland, Denver and Nashville require them in new construction of a certain size. Today, even the McDonald's world headquarters in Chicago sports a fuzzy, green top.

"One of the things I really like about it is the addition of biodiversity," says Mumford. “I've got milkweed all over mine, so I see butterflies all the time, and birds and bees. It's a nice little wild spot."

WHAT IS A GREEN ROOF?

Green roofs feature plants growing on top of a manufactured structure. They include a hefty waterproofing layer, soil or other growing medium, and usually a root barrier, plus drainage and irrigation systems.

"What we build most is what I call an eco-roof," says Mumford. "It's got 4 to 6 in. of soil and native plants, so the roof uses as little water as possible." Green roofs can be pricey, especially if you're retrofitting your house to accommodate one.

But if you have the means, they pay off economically, environmentally and aesthetically.