Stormwater Systems Benefit from Green Roofs

Publish Date: July 16, 2016
Publisher Credit: Forester Daily News

(July 16, 2016) Excerpt from an article in Forester Daily News

Green roofs – also known as vegetated or garden roofs – are key green infrastructure elements and are being increasingly recognized for their “valuable ability to absorb, reduce, and delay stormwater from reaching sewers or other grey infrastructure systems,” says Richard Hayden, garden roof product manager with Chicago-based American Hydrotech.

Green roofs work by storing rainwater in several areas of a layered assembly: in open pore spaces of the growing media and within the drainage and water retention system that underlies the growing media and plantings.

The rainwater is retained until the assembly is completely saturated, and excess water is slowly released from the roof into the site’s stormwater system. Stormwater runoff volume also is reduced because of evapotranspiration, which cools the surrounding air.

What started off as an effort to add green space on buildings for purely aesthetic purposes has morphed in a very important BMP option for handling rainwater at the point where it lands on the roof, Hayden points out.

American Hydrotech manufactures and supplies waterproofing and roofing components for projects worldwide. Its flagship product is the original hot, fluid-applied rubberized asphalt, Monolithic Membrane 6125. Originally developed in the 1960s as a waterproofing element for bridge structures in Canada, MM6125 is now used for creating green roofs.

Its seamless application makes it impervious to the effects of the wet conditions that are typical of green roofs, says Hayden. In 1996, Hydrotech introduced the Garden Roof Assembly and has since supplied waterproofing, drainage materials, lightweight growing media, and plants for more than 2,000 projects in the US and Canada.

“There are many municipalities like New York; Chicago; Philadelphia; Washington DC; and Portland, Oregon, where green roofs are being encouraged through incentives of various types,” says Hayden. “These cities are part of a significant and growing group seeking out innovative ways to minimize or slow down stormwater from reaching already overtaxed sewers.”

Recent Press

  • April 3, 2017
    Wind data is a critical issue to consider when building a new structure. An increase in the number of green roofs on buildings has driven a need for new wind design standards to be written for vegetative roofing assemblies. Richard Hayden discusses...
  • September 27, 2016
    (September 28, 2016) Washington State has always been considered a pioneer when it comes to the adoption of greener and more sustainable practices. One of the most sustainable practices is to reuse an already constructed building and enhance that...
  • July 16, 2016
    (July 16, 2016) Excerpt from an article in Forester Daily News Green roofs – also known as vegetated or garden roofs – are key green infrastructure elements and are being increasingly recognized for their “valuable ability to absorb, reduce, and...
  • July 1, 2016
    CHICAGO, ILLINOIS (July 1, 2016) City Creek Center in downtown Salt Lake City, Utah, is one of the largest mixed-use urban developments built in the last 10 years. It's also one of the most innovative. Completed in 2012, the 23-acre project includes...

Upcoming Events

    November 8, 2017 to November 9, 2017

    USGBC 2017 International Conference and Expo

    Boston Convention & Exhibition Center – Boston MA Event Details
    March 24, 2018 to March 25, 2018

    2018 RCI International Convention & Trade Show

    Marriott Marquis Houston | George R. Brown Convention Center – Houston TX Event Details