Interdisciplinary green roof growing atop Langford building

Green roofs also absorb storm water and decrease runoff, improve air quality and turn an unused space into a potential commercial or recreational space.

Students built the green roof from scratch, propagating plants, building modules, installing roof protection tiles, a drainage layer, soil, an irrigation system and the weather station.

“Most of the plants are succulents, which are very good at conserving water,” said Kirk Laminack, a graduate horticulture student who helped install the green roof. “They keep a lot of water in their stems and conserve it so they can survive droughts.”

Succulents, he added, are accustomed to hot climates but sometimes the winter is what kills them, not the summer, because it gets too cold.

“The species we planted are limited not only by heat and rainfall but by the thinness of the substrate we’re using,” said Teresa McIntyre, a horticulture major. “Using just a few inches of substrate is an important part of the experiment because many people who want a green roof cannot afford the higher cost of using deeper soil and most buildings cannot handle the added weight.”

The weather station on the roof will keep track of weather conditions.

“I’m now confident I can build a greenroof without instructions and I understand the science behind its environmental benefits,” said Bartzen.

The project builds on Dvorak’s earlier Langford green roof [research] (http://archone.tamu.edu/college/news/newsletters/spring2009/stories/Dvorak_greenroof.html) , which he began in 2009.

Installation is scheduled to continue in the spring 2012 semester with the addition of herbaceous plants, which die completely at the end of the growing season or when they have flowered or fruited, and then grow again from seed.

The project also calls for students to design and build a living wall, a vegetated wall that achieves benefits similar to green roofs and investigate its performance.