Green Roofs & Sustainability

green-roofIt might seem strange to include information about roofs when discussing sustainable land use, but roofs, like the ground, present many opportunities for creative ways to make your home more sustainable. Rooftops can be for a surprising number of things, from energy production to gardening, or just simply redesigned to make your home more energy efficient. Roof space goes largely wasted in many areas. What’s more, traditional roofs contribute to the urban heat-island effect and do not aid in storm-water management, and thus contribute to cities’ environmental problems.

Why Not Regular Shingles?

Before we talk about specifics for rooftop uses, it’s important to understand why you would do anything at all with your roof. The heat-island effect is associated with traditional roofs, and is a problem at affects urban areas when it’s warm outside. Cities are filled with dark-colored, impermeable materials like shingles and asphalt that absorb much more heat than things like plants and trees that are more common in rural areas. Roofs are an area that often dark-colored and by definition impermeable, and traditional roofs contribute to the heat island effect, which in turn raises cooling costs, contributes to air quality and public health problems, and can even impair water quality. Traditional roofing materials also contain some toxic substances and do not absorb any water, so when it rains they contribute to storm-water runoff and can potentially leak toxins into that water. Are you ready to redo your roof yet?

What You Can do Instead

One of the main determinants of what you can use your roof for is its shape and position. When thinking about how to use your roof, the first think you should consider is its shape. You won’t have an easy time trying to garden on a roof that isn’t flat, so that will limit your choices from the start. Assuming the structure of the roof is strong enough, both flat and pitched roofs allow for

  • green roofs
  • solar panels
  • reflective roofing
  • rain water harvesting

You can also use a flat roof as a garden, which is a great option is more dense urban areas or if you have a green thumb.

The next thing to consider is the position of your home, though this is less significant, especially for flat roofs. Obviously, solar panels need sunlight to produce power and plants need sunlight (generally) to grow, so if your roof is shaded, which often is the case for at least one side of a pitched roof, you will be even more limited. On the plus side, if your roof is completely shaded it won’t absorb as much heat and it won’t contribute as much to the heat-island effect.

While there isn’t enough space here to go into depth on each of the different uses for a rooftop, hopefully we’ve got you thinking about the possibilities. Some of the above solutions will save you energy and money, and some are just good for the environment and are the right thing to do.

Behind the Walls
Innovation Center
One Broadway
Cambridge, MA 02142