The amazing benefits of green and living roofs.

In part one of this series, we documented the amazing concept of growing grass, shrubs, trees, and even food on top of houses and buildings that can help clean up our environment and provide natural beauty. In this blog, we'll cover the benefits and drawbacks of green roofs, and a few resources if you wanted to learn more or consider a green roof for your home.

Benefits of green and living roofs:

Noise reduction:

Living roofs are extremely effective sound barriers, helping to drown out the noise of traffic or commerce in busy urban areas. The Chicago City Hall uses a living roof for this reason, and some homes under the flight path of San Francisco International airport have installed living roofs to help reduce the sound of the airplanes. Studies show that these living roofs can reduce noise levels by up to 50 decibels, and even a thin and basic grass roof will drop the outside noise by 5 decibels.

Water runoff control:

A living roof does a great job naturally regulating runoff from heavy rains and storms. Since vegetation and organic materials absorb rain, up to 42% of runoff, or about an inch of rainwater, is captured that would otherwise be wasted. That helps control flooding, overwhelming irrigation and sewer systems, and protects the natural balance of water.

Natural insulation:

Living roofs naturally cool down the outside air by acting as a heat barrier and also keep warm air inside the house in wintertime. Since heat rises, most of your energy loss is through the roof when you turn the heat on in the cold season. But living roofs can help keep you cool or warm, regulating the outside temperature by approximately 10 – 25 degrees Fahrenheit. The great thing is that the hotter the climate and outside temperature, the better an insulator a living roofs is, saving a lot of money on energy bills in warm climates.

Pollution control:

Trees, plants, and grasses help to alleviate the harmful effects of manmade pollution by converting carbon dioxide and other toxic gases into breathable oxygen. Installing livable roofs on big commercial buildings and office spaces in urban areas will not only slow the capture of gases, or greenhouse effect, and help filter airborne particles and pollutants that wash off into the soil. In fact, studies have shown that green roofs can trap up and filter out up to 95% of heavy metals that are caught in the water cycle.

Food production:

The renewed focus on producing organic, locally grown healthy food has vast potential when it comes to rooftops. Already, schools and many urban centers and office buildings are starting to grow fruits and vegetables on rooftops. Green roofs can also become hosts to edible growth and food production, especially on flat surfaces.

Fire resistance:

While it may seem like organic grasses and growth on rooftops may be more susceptible to fire, like we see with forest fires, in reality the soil and organic matter is actually fire resistant. Green roofs also hold a good deal of moisture that will thwart fires and burn slow, if at all. In fact, a “bare” roof of just shingles over wood is far more likely to a fire starting, especially over time as the surfaces are weathered and dry out.

Water filtration:

Green roofs on large surfaces can also act as natural water filtering mediums. In Australia, they are already using green roofs and walls as a natural filter to treat domestic grey water and wastewater, removing organic matter and pollutants.

A host to living things:

Green roofs serve as a natural micro ecosystem and that includes becoming home to a variety of birds, butterflies, and bees. Some people may not be comfortable at first with the idea of a lot of critters living on and in their roof, but as human beings overtake the landscape with pavement and pollution, the loss of native fauna is alarming. Already the huge extinction of bee populations is affecting our food systems and health. Green roofs can help reverse that trend, as we see with a large U.S. auto manufacturer who has built a giant bee farm on the roof of one of their factories.

Drawbacks and questions about green roofs:

Of course green roofs take some planning, work, and cost to install and maintain, but once you learn more, you’ll realize it’s well worth it.

Weight of the roof:

Green roofs are heavier than normal roofs, varying widely based on the depth of soil and the type of vegetation grown. Most green roofs weight only a little more than slate roofs, but weight can be a concern that should be carefully planned before any installation starts. It’s relatively simple to retrofit beams and columns of the existing roof to reinforce it for the weight.

Cutting and maintenance:

You probably only get near your roof when you clean out your gutters once or twice a year, but green roofs do take some maintenance. But don’t worry – when you’re mowing the lawn, simply take the weed whacker or hedge trimmers up onto your roof and cut everything back once or twice a year. Other than that, just check on the irrigation system and that’s all the maintenance you’ll need.

Watering and drainage:

In most climates, rainwater will be sufficient to keep your living roof green and thriving most of the year, but in the summer or arid climates homeowners can augment that with irrigation systems that are installed when it’s first built.

Likewise, green roofs have built in drainage systems similar to gutter and downspout systems on any roof.

Where can I get more information?

A green roof can help the environment, lower your energy costs, provide scenic beauty for your family, and also increase your home’s value. So where can you find out more about installing a living roof on top of your house?

Green roof facts. 

Is a Green roof right for you? 

Green roofs discussed by the U.S. Environmental ProtectionAgency (EPA).

Look up. The Green Roof Revolution is coming.

Look up. The Green Roof Revolution is coming.

There will come a time soon when if you walk outside and scan the horizon, you’ll see tranquil green gardens as far as your eyes can see, not the drab brown and black rooftops we see now. Everyone will have grasses, natural vegetation, and flowers on the top of their homes, sprouting and changing colors with the seasons and attracting birds, butterflies, and endangered bees to flourish in their new rooftop habitats. Even commercial buildings will have green roofs, with full trees, water gardens, and organic fruits and vegetables produced in space that is wasted now.

Thanks to these green or “living roofs,” there will be less pollution, cleaner air, less water waste, less noise pollution, and our energy costs to heat or cool our homes will be lower.

Does it sound like something out of a futuristic sci-fi society – or only for the ultra modern homes of the super wealthy? In fact, living roofs and already here and being used around the world, growing fast in popularity as we better understand and focus on the consequences of our mass ecological footprint.

 In this blog, we’ll cover some of the basics of living roofs (and living walls.) In part 2, we’ll go into the amazing benefits in detail and also outline the installation and maintenance process if you wanted to add one to your home!

What are living roofs?

Green roofs, also called living roofs, is when a residential or commercial building has a specially constructed micro ecosystem of grasses and vegetation installed as the top layer on its roof surface. The roof can be flat, sloped, or pitched just like any roof. But instead of using a top layer of shingles, slate, rubberized membrane, or other traditional roofing materials, vegetation is grown in a thin layer of topsoil or organic medium that lies on top of waterproof sheeting.

There are also living walls, which can be incorporated into horizontal living spaces large or small, indoors or outdoors. Living walls are usually either grown from specialized posts that hang affixed to the walls, with plants growing up a climbing net, trellis, or similar structure, or grown right out of an organic membrane that hangs on top of regular sheetrock and includes specialized irrigation and drainage. For the purposes of this blog, we’ll include living walls whenever we say living roofs or green roofs.

There are terrific benefits to living roofs and living walls, both for the homeowner or resident, the immediate neighborhood or city, and to the ecosystem of our world as a whole.

Why are living roofs so important?

You only have to turn on the television to hear calamitous reports of climate change, global warming, and draught. And as our world gets more populated, our urban areas become more dense, with more buildings and pavement and less trees, grassy areas, and natural habitats. Rivers and waterways are more polluted than ever and at the same time, human beings are toxifying the environment to the point where other species of animals are being killed off or crowded out.

But every building has a roof, which becomes completely wasted space 99.9% of the time. The good news is that not just environmentalists and scientists but the average person is starting to understand the mutual benefit to installing solar panels to capture energy and lessen their environmental impact. Or now, living roofs.

Living roofs have some amazing benefits to the environment, and with almost 120 million homes (or households) in the U.S. alone, and countless other large commercial spaces, imagine the positive impact if they were all utilized to “green” our society.

Where can living roofs be found?

Living roofs may seem ultra-modern, but they’ve been used for over 1,000 years around the world, from the Vikings with turf living roofs in Scandinavia to traditional living roofed cottages in Ireland and Scotland.

Germany has been very progressive with clean energy and clean environmental practices, already having used living roofs for 30 years. The German government encourages Green Roof building through their Federal Nature Protection Ac as well as building codes and incentives. In nearby Austria, cities like Linz mandate green roofs for new residential and commercial buildings over a certain size. The UK has been experimenting with green roofs, anchored by the living roof atop the notable Rolls Royce showroom. And in Australia, living roofs are starting to take hold and grow in popularity.

In the United States, living roofs are still rare – mostly seen only in ultra modern and luxury, cutting-edge architecture. But already in many cities like New York, Chicago, and San Francisco, the idea of rooftop gardens on urban buildings is becoming prevalent, a precursor to familiarity and comfort with living roofs.

What kinds of living roofs are there?

There are generally two types of living roofs; intensive and extensive.

Intensive living roofs have deeper soil and can support all sorts of large vegetation up to the size of full trees. Most rooftop gardens are intensive roofs.

Extensive living roofs have a much shallower growing surface that hosts groundcover vegetation like grasses.

Of course, there are all sorts of rooftop gardens where people grow flowers, fruits and vegetables. Those may have similarities but usually are built separately and after the fact on top of a traditional roof, not incorporated into the roof itself.

What kind of vegetation do living roofs use?

There are different kinds of grasses and vegetation commonly used in living roofs. What you use depends on your climate, what plants are native to your terrain, how much rain and sunlight you get, and how deep the soil or growth membrane is on your roof.

When first setting up a living roof, installers and homeowners usually plant at least four different grasses for several reasons. Some of them may not take root or flourish so it’s good to have several varietals. And with different kinds of grasses or vegetation, you’ll have different blooming times and colors during different seasons.

So living roofs usually look like wildflower meadows, not tightly cropped short grass on our front lawns (which isn’t healthy and takes much more water.)

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Tune in for part 2 of this blog, with the benefits of living roofs as well as information on installation and maintenance.