Different Types of Green Roofs on Grounds

The University of Virginia and the surrounding Charlottesville area have some stunning examples of green roofs. However, these green roofs can vary considerably. As we prepare to analyze them, we want to talk a little about the general benefits of green roofs and the different green roofs we might encounter.

Green roofs are impermeable surfaces that can filter rainwater and reduce storm runoff. Plants on the roof filter not only pollutants from the water, but also pollutants from the air. Green roofs can also provide insulation for the building, saving both energy and money during hotter days. Currently UVA has about 10 green roofs, with hopes of increasing that number in coming years. These green roofs can be classified as intensive, extensive, or somewhere in between. Each type has their own benefits and drawbacks, and a mix of these different types can be found on grounds.

An extensive green roof has a shallow substrate, is relatively light, and is low cost and low maintenance. They are typically composed of mosses or sedums and require little to no irrigation. Examples of this type of green roof at UVA include the Medical Research Building and Garret Hall.

Extensive Green Roof on Garret Hall

An intensive green roof has a very thick substrate. It is very heavy, more expensive, and is more difficult to maintain than an extensive green roof. It also requires irrigation. The substrate is deep enough to support large shrubs or trees, so it can be used for more human-centered purposes, such as gardens or parks.  Examples of this type of green roof on grounds include the Carter Harrison building as well as the Special Collections Library.

The Carter Harrison building featured to the left; The Special Collections Library featured to the right 

These are just a few examples of the green roofs on grounds, and we will go into more detail about specific green roofs and how they were constructed in later posts. Throughout the rest of the semester we hope to visit as many as we can in order to analyze their beauty, use, benefits, and possible improvements. We will also be on the look out for places of future green roofs and how they could be more accessible for student study spaces.

Post by Amanda Demmerle, Second Year, Environmental Science and Environmental Thought & Practice

Photos retrieved from http://www.officearchitect.virginia.edu/pdfs/Green_Roof_illustrated_guidelines_Dec2013.pdf