Sustainability

Green roof manufacturers take a hard look at sustainable materials

Green roof manufacturers incorporate sustainable products beyond the greenery.

Fabric Architecture | March 2008

By Jake Kulju

Porous pavers are another smart sustainable application. The Netpave® 50 system, from Conwed Plastics, is made from 100% recycled polyethylene, helping to reduce stormwater runoff and increase infiltration.

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Make it last

Brad Budde of Conwed Plastics, Minneapolis, Minn., believes the future development of sustainable green roof products lies in the hands of builders. He suggests that as companies continue to understand the commercial concerns regarding the application of sustainable and earth friendly products that the market as a whole will become more educated about their applications, benefits and uses.

“Conwed works very diligently on two fronts with our biodegradable and earth friendly materials,” says Budde. His company is a leader of earth friendly, compostible packaging materials as an alternative to traditional plastic bags, as well as biodegradable plastics that don’t leave the harmful, long lasting resins of other industry plastics. “It’s a really great product that solves some of the disposal concerns for traditional plastic products,” he says.

One of Conwed’s most earth friendly products is its erosion control blanket netting. While not typically used in green roof applications, it is nonetheless a big step toward creating holistically green products. “The temporary rolled erosion control products are meant to stabilize the ground until vegetation comes in and provides natural stabilization,” Budde says.

Jeff Stillman of ZinCo USA, Newton, Mass., says one of the keys to his company’s sustainable green roofing products is the use of non-rotting, recycled polypropylene. The substance’s long lasting capabilities and recycled nature make it a shoe-in for sustainable building material. “It’s the fabric that we use for our protection mat and fi lter sheets,” Stillman says. “The mat is needle punched and usually made with a fleece backing composed of recycled polypropylene fibers.”

Putting it all together

Carlisle SynTec, Carlisle, Penn., has an entire manufacturing sector for their Roof Garden materials. The company creates green roofing layers that include a drainage board, protection fabric, root barrier and a moisture retention mat all made of mostly recycled polystyrene and polypropylene material.

The drainage board is of particular interest. Used as an alternative to drainage gravel and a supplement to protection fabric, Carlisle SynTec’s MiraDrain HC drainage board is made of high impact polystyrene covered by non-woven polypropylene filter fabric. Similarly, the company’s root barrier product, the GeoMembrance™, is made of non-reinforced polypropylene fabric.

Top of the heap

Sustainable materials aren’t confined to the base level of green building projects. When it comes the greenery on a green roof, plants come into play. Ed Snodgrass of Emory Knoll Farms, Maryland has provided plants for 268 roof projects, providing more than 2 million square feet of green roofing in the U.S. Snodgrass’s farm is in collaboration with several university research programs. The effort is producing a fund of knowledge about soil depths and plant types that create healthy, lasting and sustainable green roofing projects.

The Emory Knoll farm employs photovoltaic panels, bio diesel engines and composting toilets all to save and create sustainable energy. All of the farm’s plants are chemical free. “We try to produce as much energy as we can,” says Snodgrass. “So as we can afford to make capital improvements, we want part of that capital to go to energy production of some kind.”

Jake Kulju is a regular contributor to Fabric Architecture. His article on the Abteiberg Museum appeared in the Sept/Oct issue.

Porous pavers are another smart sustainable application. The Netpave® 50 system, from Conwed Plastics, is made from 100% recycled polyethylene, helping to reduce stormwater runoff and increase infiltration.
Considered a “semi-intensive” system of green roof, the China World Tower complex, in Beijing, permits growth of vegetation and perennial gardens, reducing stormwater runoff and AC load.
Conwed’s linkable modules lock neatly together to form a stable surface.
ZinCo’s 60mm deep drainage element provides water storage for plants, as well as drainage of any excess water beneath.
To reduce the heat-island effect in urban areas, one method found especially effective in Europe is a hybrid green roof system that incorporates walkways over a carpark. This project, located in Weisbaden, Germany, uses a system supplied by ZinCo.
Biodegradable and earth friendly erosion control blanket netting, from Conwed Plastics, is sometimes used to stabilize a groundscape or green roof system until vegetation establishes and provides natural stabilization.