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HyGRO-Green Roof Optimum System

Green Roof Drainage System Products

Of all the choices the owner or specifier has to make when designing a green roof drainage system, the choice of waterproofing is easy. The Hyproof membrane is a high-performance Coal Tar Elastomeric Membrane (CTEM).

Incorporating the modern benefits of DuPont™ Elvaloy® and the time-proven properties of coal tar pitch, Hyproof has passed the 2-year FLL root barrier test and proved itself a superior waterproofing barrier for green roof systems.

Green Roofing Systems Products

HyGro DB 50

A prefabricated product that consists of a formed and perforated core covered with a soil filter layer and a fabric protection layer. The filter fabric is securely bonded to prevent soil intrusion into the core flow channel while allowing water to freely enter the drainage core. Sheet drains allow water entry from one side and are typically used to collect and re-direct water from below the growing medium of a green roof system.

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HyGro DB 100

A prefabricated product that consists of a formed and perforated core covered with a soil filter layer and a fabric protection layer. The filter fabric is securely bonded to prevent soil intrusion into the core flow channel while allowing water to freely enter the drainage core. Sheet drains allow water entry from one side and are typically used to collect and re-direct water from below the growing medium of a green roof system.

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HyDrain 650

A prefabricated product that consists of a solid, formed, three dimensional core covered with a geotextile filter fabric bonded to the dimple side of the core. The filter fabric is securely bonded to prevent soil intrusion into the core flow channel while allowing water to freely enter the drainage core. Sheet drains allow water entry from one side and are typically used to collect and re-direct water from below the growing medium of a green roof system.

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HyBase SAM

HyBase SAM is a self-adhering, high performance, thermoplastic roofing membrane compounded with a proprietary combination of coal tar pitch, and Dupont™ Elvaloy® KEE resins, reinforced with dispersed polyester fibers. An SBS adhesive and release paper are applied to membrane in a separate process.

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HyProof SA

A self-adhered, coal tar elastomeric (CTEM) waterproofing membrane. Its primary components are coal tar pitch, PVC, and DuPont Elvaloy® KEE resin.

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Green Roof Drainage System

Besides the Critical Property of Root Resistance, The Hyproof Membrane for Green Roof Systems Also Offers:


  • Hot-air welded seams for system integrity – no lap adhesives that can be attacked by chemicals or roots
  • Extreme chemical resistance
  • Mold, rot and mildew resistant
  • Puncture resistant
  • Unaffected by ponding water – can be warranted on zero slope

The Hyproof membrane, along with our full line of accessory products, will provide the optimal, long-lasting waterproofing choice for any and all green roof systems.

Structural


The structural capacity of the building and roof deck must be able to support the added dead load of the green roof when saturated with water following a rain event. For a simple extensive roof using lightweight media this will be about 7.5 lbs. per square foot of roof per inch of media depth. For intensive roofs with heavier media and larger plants, this could be much greater. Roofs with a slope greater than 2 in 12 may require supports to stabilize the roof system. Insulation, if used, must have sufficient compressive strength that can withstand the dead and live loads.

Drainage


Drainage is needed to allow excess rainwater to flow off the roof. Drainage can be a coarse granular material or a synthetic layer. Granular drainage may be lightweight aggregate like lava rock, or expanded clay, slate or shale. If the structure can support the weight, gravel or crushed brick or other similar material can be used. Granular drainage layers are typically 2″ thick. Using granular drainage can replace some of the media thickness required. Synthetic drainage sheets will be lighter and are typically 1/2″ thick. Regardless of the type of drainage used, it should always be separated from the media by a filter fabric to prevent fines from the media filling the drainage.

Media


Media selection is critical to the success of a green roof. Considerations include weight, stability, water-holding capacity and hydraulic conductivity. Most lightweight commercial media combine a lightweight aggregate like expanded clay, slate or shale (80-90% by volume) with organic compost (10-20% by volume). For extensive green roofs using commercially available lightweight media, the optimal media depth is 3.5″ to 4.5″. This gives the best balance when considering the necessary structural strength of the building, the cost of media and vegetation, the moisture-holding capacity (stormwater management) and maintenance requirements. If the building can support greater weight, less-costly materials like fine gravel and sand can be used. In either case, the media should be tested and meet FLL guidelines for the type of roof.

A helpful resource concerning green roof media can be found here.

Green Roof Drainage System Projects


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