Sometimes a green roof is exactly what it sounds like.
The green movement is everywhere. So much so that it’s no longer a peculiarity, but more just the way things are. Green roofs have been a part of that movement, but they aren’t as new as you might think.
They’ve been around for more than just a long time; they might even be considered ancient technology. Maybe everything old really is new again, but this time it’s with some improvements.
Green Roofs Once Covered Caves and Huts
Long before any college of architecture ever exited, early builders understood the need for protection against the elements. Not just protection from rains, but also from the heat of the sun and to contain warmth during cold weather.
Sod roofs were an ancient building material, according to Green Roof Technology, and they served to protect cave homes and later huts and other structures.
Common in many different parts of the world, sod roofs have been found (and are still in use) in areas such as Finland, Norway, and even the United States. Thatch, which is dried vegetation layered onto a roof, is another common green roofing material used in locations such as Ireland, England and Holland, and is gaining a new following.
Almost any house can support a green roof, but flatter roofs work better for gardens and other unsecured materials.
What Makes a Green Roof Green
Roofs have one obvious function, which is to protect a structure from the elements. But once that fundamental need is met, there’s a lot more that a roof could, in theory, do.
A green roof helps insulate a home or commercial building, which keeps those structures cooler in summer and warmer in winter. They can also help contribute to cleaner air.
The cleaner air factor happens in two ways. First, with plant life on the rooftop, toxins are filtered and oxygen is produced through photosynthesis. The very thing that humans need to breathe, plants produce as a byproduct. Second, the soil and plants create that insulating layer to reduce heat transfer all year long.
Reflective, white roofing materials send heat back to its source instead of absorbing it.
Alternatives to Plant Life
Green roofs might very well conjure thoughts of plant life, and that’s one common approach, which the EPA supports. Even some city buildings have greenscapes up top to help insulate and reduce passive solar heat gain in summer and heat loss in winter. But while grasses, flowers and even shrubs are the typical idea, there’s more to green roofing than growing a garden overhead.
Some experts promote white roofing materials reflect away the sun’s rays, which reduces solar heat gain, as the better option. Their arguments include the cost of paint versus garden maintenance and water consumption, and the fact that paint reflects instead of absorbs heat.
On the pro side of gardens, you get cleaner air. But Sierra Club says that science supports the theory that reflective paint is 3 times greener than rooftop plant life.
No matter how you approach it, a green roof is a better option than traditional roofing materials, at least as far as environmental effect is concerned. Asphalt shingles might shed water, but they do little to reduce heat transfer. And they’ve never produced oxygen or filtered the air.
Although green roofing might not have been at the forefront of anyone’s mind when sod and thatch roofs were being installed around the world, the fact remains that they did get it right. There’s an uptick in natural roofing installations, and reflective paint is having its day in the sun, too. It’s all about progress and what’s better for society, and green solutions are always part of that.
Architects are leading the green movement way, and that’s due in part to continuing education. When you need professional development hours for your licensing and association memberships, check out our courses at PDH Academy. We make green technology continuing education courses straightforward and hassle free.