Extensive Garden Roof® Assembly

The Extensive Garden Roof® Assembly is ideally suited for locations that will receive little maintenance or where structural capabilities are a concern.

Unlike Intensive Garden Roof Assemblies, Extensive Garden Roofs are not intended for recreational use and are typically chosen for their appearance or to help reduce the "urban heat island" effect and minimize stormwater run-off. Extensive roofs only require a shallow growing media depth, generally as little as 3"-6" (depending on the region), and therefore add little weight to the roof structure below when compared to a standard ballasted PMR roof.

Recommended plant types for extensive roofs need to be drought, wind and frost resistant, such as self-generating sedums, herbs, grasses and other vegetation that can withstand harsh growing conditions.

The water stored in the growing media and drainage/retention layer is sufficient to sustain the drought resistant plants between periods of normal rainfall. Thinner assemblies and very lightweight growing media blends are available for Extensive Garden Roof Assemblies. Contact us for specifics.

Features of the Extensive Garden Roof Assembly:

  • Depth (3” - 6” of growing media)
  • Reduce and delay stormwater runoff
  • Help to mitigate the urban heat island effect
  • Requires minimal maintenance
  • Can be used on flat or sloping roofs
  • Garden Tray GT15™ available for modular applications
  • Vegetation options - plugs, cuttings, InstaGreen™ Sedum Carpet or InstaGreen™ Sedum Tile

Typical Application:

An Extensive Garden Roof Assembly can be applied to flat roofs and sloping roofs with a pitch of up to 12:12 or 45°, provided the appropriate measures are taken to cope with the shear forces and soil retention. Extensive roofs are typically lightweight and can be installed over a variety of structures including metal roof decks.

Recent Press

  • October 20, 2016
    (November 15, 2016) Richard Hayden, Hydrotech's Garden Roof Department Manager, will be speaking at the 2016 LED Specifier Summit and High Performance Building Forum. The design community continues to struggles with how to handle ever-increasing...
  • September 24, 2015
    (August 5, 2016) Excerpt from an article in Stormwater Magazine . With their myriad benefits, green roofs are becoming increasingly incorporated into new and existing projects. The International Green Roofs and Walls Project Database lists 1,599...
  • 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...
  • July 2, 2014
    American Hydrotech Inc. has released a free, interactive digital version of the company's popular Garden Roof® Planning Guide. The app – unveiled last week at the AIA Expo in Chicago – features pinch-to-zoom product photography, video animations, photo galleries showing Garden Roof® Assemblies in real-world applications, and design considerations.
  • September 5, 2014
    CHICAGO, ILLINOIS (September 5, 2014) American Hydrotech, Inc., a recognized leader in the development and distribution of premium waterproofing and roofing products, is pleased to announce that Garden Roof® Assembly and Ultimate Assembly technology...

Upcoming Events

  • May 31, 2017 to June 2, 2017

    2017 Great Lakes and St. Lawrence Green Infrastructure Conference

    Cobo Hall – Detroit MI Event Details
  • October 21, 2017 to October 22, 2017

    ASLA 2017 Annual Meeting and EXPO

    Los Angeles CA Event Details
  • November 8, 2017 to November 9, 2017

    USGBC 2017 International Conference and Expo

    Boston Convention & Exhibition Center – Boston MA Event Details