Greenroofs in the news

Three interesting articles today:

1. NPR outlines the benefits of green- and cool roofs.

2. Another rooftop farm in NYC, started by one of the people that developed the one in Greenpoint.

3. Systems for making sure your greenroof doesn't leak.

Green roofs and walls

I've made a couple of cool discoveries over the past couple of days and wanted to share them.

First, in our quest to find the perfect wedding venue, my fiancee and I took to Durham, NC. While we didn't find a spot for vows, we did find a new parking garage at Duke -- complete with greenroofs and walls. A couple of photos, and a couple of links:

Here's some information and a few graphics that picture areas that I couldn't capture.

The garage follows tenets outlined in the New Campus Master Plan (essentially, the redevelopment of the old Central Campus).

Second, I got a note from a client yesterday with images of a greenroof we installed at the end of last summer (see below). So far, so good! The sedum should fill in the gaps this summer.



Last, but not least: Columbia and Con Ed have teamed to assess the insulating and cooling capacities of cool roofs (white roofs and greenroofs) vs. conventional black roofs (tar beaches!). In a very interesting study released last week, the group found that green and white roofs perform roughly equally in preventing heat island effect (through evapotranspiration and albedo, respectively) and that each limited temperature variability enough to produce modest energy savings. There is concern, however, that the performance of older white roofs may suffer since the reflectance of these roofs declines as they age. White roofs also lack the ability to moderate water flow, improve air and water quality, provide habitat and recreation space, and improve aesthetics for nearby neighbors, six of the primary motivators for greenroof installation. A very interesting study and I look forward to reading future research findings...

White light/white heat

The New York Times featured a story today on the energy benefits of white roofs. The article speaks to the savings that white roofs produce in hot climates, while acknowledging that they are not a panacea; in cities like Minneapolis and Detroit, scientists suggest that white roofs can actually lead to increased energy bills since they reflect light (and heat) during cold winter months.

While I can't refute evidence on the suitability of white roofs in northern climes, I certainly can speak to the benefit of green roofs. The beauty of the green roof is that it buffers temperature extremes, whether hot or cold. If you're skeptical, plug "green roof energy savings" into Google Scholar and see what comes up. (Start with these: "Analysis of the green roof thermal properties and investigation of its energy performance" by Niachou et al. and "The effects of rooftop garden on energy consumption of a commercial building in Singapore" by Wong et al.).

I'm not sure why the author didn't think it appropriate to include green roof information in the article, but I sure wish that there were a comment section on this one...