Extensive - Garden Roof Assembly

As our cities continue to grow, the natural landscape is being replaced with buildings, as well as parking lots and roadways of concrete and asphalt. Open green spaces within city centers are decreasing as the strong demand for land to build upon increases. Temperature increases of 3-10°F have been observed in city centers when compared to temperatures in outlying areas where Mother Nature is part of the natural surroundings.

Commonly referred to as "urban heat island" effect, this dome of heat creates an unhealthy environment in which polluted air, smog and higher temperatures can take their toll on us all. Additionally, these increased temperatures result in higher energy demands to keep our buildings cool.

To a great extent the rooftops, parking lots and roadways that make up the cityscape are impervious to water, often resulting in an overload of the existing drainage and sewer systems, increasing the risk of flooding following a heavy rain. Continued development in our cities will only add to this problem, making the cost for improving the existing sewer infrastructure prohibitively expensive.

Hydrotech`s "Total" Garden Roof Assembly Approach

From the roof membrane up through the plants, at American Hydrotech we understand that a vegetated roof needs to function first as a roof, keeping the structure watertight, and at the same time provide an environment conducive to the vegetation. In our Garden Roof Assemblies we accomplish this by incorporating the very best in moisture protection, proven vegetated roof technology and experience. Learn more about why a Hydrotech Garden Roof Assembly is the ideal solution for your next vegetated roof project

Garden Roof® Assemblies

Hydrotech`s wide range of Garden Roof Assemblies are available to suit virtually any design requirement. They are typically classified as:

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
• InstaGreen® GT-4 Tray available for modular applications
• Vegetation options - plugs, cuttings, InstaGreen® Sedum Carpet or InstaGreen® Sedum Tile

• Extensive
• Sloped Applications
• Intensive
• Lawn
• LiteTop Media
• Plant Options
• Rock Wool Assembly
• Stormwater

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.