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[[File:Pass Filter Bed green roof.PNG|400px|thumb|right|Fully constructed green roof.]]

[[File:Pass Filter Bed green roof.PNG|500px|thumb|right|Fully constructed green roof.]]

 

=Overview=

=Overview=

[[Green roofs]] are composed of several layers (waterproof membrane or existing membrane, root barrier, drainage layer, filter fabric, growing medium) that support the growth of plants and other vegetation on top of a roof. Growing medium depth determines which plants can be planted, and the components of green roofs can either be loose-laid or fused together. The proper installation of green roofs can help to achieve water balance targets, promote biodiversity and provide green space. Some key resources for green roof construction include the following:

[[Green roofs]] are composed of several layers (waterproof membrane or existing membrane, root barrier, drainage layer, filter fabric, growing medium) that support the growth of plants and other vegetation on top of a roof. Growing medium depth determines which plants can be planted, and the components of green roofs can either be loose-laid or fused together. The proper installation of green roofs can help to achieve water balance targets, promote biodiversity and provide green space. Some key resources for green roof construction include the following:

=Types=

=Types=

There are two main types of green roof systems: extensive and intensive.

There are two main types of green roof systems: extensive and intensive.

#Extensive green roofs have growing medium depths of 10 cm to 15 cm (0.1 m to 0.15 m), maximum structural weight loads of 250 kg/m², and vegetation is primarily limited to sedum ''spp'' or commonly known as stone crop. For information on plants that are often included in extensive green roofs, see [[Green roofs: Planting|this list]].

#'''Extensive green roofs''' have growing medium depths of 10 cm to 15 cm (0.1 m to 0.15 m), maximum structural weight loads of 250 kg/m², and vegetation is primarily limited to sedum ''spp'' or commonly known as stone crop. For information on plants that are often included in extensive green roofs, see [[Green roofs: Planting|this list]].

#Intensive green roofs have growing medium depths greater than 15 cm (0.15 m), no maximum structural weight load. Intensive green roofs can be planted with deeply rooted plants, making them suitable for various [[Perennials: List|native flowers]], [[trees]] and [[shrubs]]. Pedestrian pathways and gathering areas can also be incorporated into the design of intensive green roofs.  

#'''Intensive green roofs''' have growing medium depths greater than 15 cm (0.15 m), no maximum structural weight load. Intensive green roofs can be planted with deeply rooted plants, making them suitable for various [[Perennials: List|native flowers]], [[trees]] and [[shrubs]]. Pedestrian pathways and gathering areas can also be incorporated into the design of intensive green roofs.  

Within these two types of green roofs are two installation type systems:

Within these two types of green roofs are two installation type systems:

#Modular system: green roof component layers are fused together as a moveable modular block system that can be linked together with other green roof blocks to form the green roof. This type of system typically forms an extensive green roof type and are used where roofs are sloped and flat.

#'''Modular system''': green roof component layers are fused together as a moveable modular block system that can be linked together with other green roof blocks to form the green roof. This type of system typically forms an extensive green roof type and are used where roofs are sloped and flat.

#Layered system: all components' layers are loose laid as individual layers. This type of system can form both extensive and intensive green roofs and used typically on flat roofs.

#'''Layered system''': all components' layers are loose laid as individual layers. This type of system can form both extensive and intensive green roofs and used typically on flat roofs.

=Component description=

=Component description=

|+ Green roof construction steps

|+ Green roof construction steps

|-

|-

!Green roof type

!'''Green roof type'''

!Construction steps

!'''Construction steps'''

|-

|-

|Modular system

|'''Modular system'''

|

|

#Sweep and blow the roof membrane clear and free of dirt, debris, and any sharp objects (such as flash clippings)

#Sweep and blow the roof membrane clear and free of dirt, debris, and any sharp objects (such as flash clippings)

|-

|-

|Layered system

|'''Layered system'''

|

|

#Sweep and blow the roof membrane clear and free of dirt, debris, and any sharp objects (such as metal flashing clippings)

#Sweep and blow the roof membrane clear and free of dirt, debris, and any sharp objects (such as metal flashing clippings)

|}

|}

<gallery mode="packed" widths=300px heights=300px>

<gallery mode="packed" widths=200px heights=200px>

GRPerimeter.JPG | Green roof perimeter installation (Photo Source: CVC)

GRPerimeter.JPG | Green roof perimeter installation (Photo Source: CVC)

GRdrainagelayer.JPG | Green roof root barrier and drainage layer installation (Photo Source: CVC)

GRdrainagelayer.JPG | Green roof root barrier and drainage layer installation (Photo Source: CVC)

Grfinishedsoil.JPG | Finished installation of green roof soil media prior to vegetation (Photo Source: CVC)  

Grfinishedsoil.JPG | Finished installation of green roof soil media prior to vegetation (Photo Source: CVC)  

GRveginstall.JPG | Completed installation of green roof sedum vegetation (Photo Source: CVC)

GRveginstall.JPG | Completed installation of green roof sedum vegetation (Photo Source: CVC)

Green Roof Shed.JPG | Modular green roof system

Green Roof Shed.JPG | Modular green roof system (Newtben33, 2013)<ref>Newtben33. 2013. Green Roof Shed. Photo. Accessed 21 September 2022. https://commons.wikimedia.org/wiki/File:Green_Roof_Shed.JPG</ref>

Toronto City Hall Podium green roof by LiveRoof, July 2010.jpg | Toronto City Hall Podium green roof by LiveRoof, July 2010

Toronto City Hall Podium green roof by LiveRoof, July 2010.jpg | Toronto City Hall Podium green roof by LiveRoof, July 2010 (GreenRoofGardener, 2010)<ref>GreenRoofGardener. 2010. Toronto City Hall Podium green roof. Photo. Accessed 21 September 2022. https://commons.wikimedia.org/wiki/File:Toronto_City_Hall_Podium_green_roof_by_LiveRoof,_July_2010.jpg</ref>

</gallery>

</gallery>

#Prior to hand-off points in the construction sequence when the contractor responsible for the work changes (i.e., hand-offs between the building and green roof installation contractors);  

#Prior to hand-off points in the construction sequence when the contractor responsible for the work changes (i.e., hand-offs between the building and green roof installation contractors);  

#After large storm events (e.g., 15 mm rainfall depth or greater) to ensure roof drainage or flow diversion devices are functioning and adequately maintained.

#After large storm events (e.g., 15 mm rainfall depth or greater) to ensure roof drainage or flow diversion devices are functioning and adequately maintained.

Additional inspections may be needed depending on the number of layers in the green roof design (e.g., insulation, root barrier, and growing medium structural support layers) and may be required to comply with product warranty conditions. The green roof product vendor or designer should provide further guidance in this regard, specific to the system or product being installed.

Additional inspections may be needed depending on the number of layers in the green roof design (e.g., insulation, root barrier, and growing medium structural support layers) and may be required to comply with product warranty conditions. The green roof product vendor or designer should provide further guidance in this regard, specific to the system or product being installed. A checklist of construction inspection steps can be found on the [[Inspection and Maintenance: Green Roofs]] page.

 

The following checklist can be used during the construction process:

 

|+'''Green Roofs: Construction Inspections'''

|Installation of drainage layer (e.g., depth and slope) is acceptable

=Mistakes to avoid=

=Mistakes to avoid=

=References=

=References=