Notes to VRA Standard - Revision history

James Klassen: /* A-1.1.3.2. Permitted Vegetated Roof Systems */

2026-07-27T18:24:09Z

‎A-1.1.3.2. Permitted Vegetated Roof Systems

James Klassen: /* A-1.1.3.2. Permitted Vegetated Roof Systems */

2026-07-27T18:19:32Z

‎A-1.1.3.2. Permitted Vegetated Roof Systems

James Klassen: /* A-1.1.3.2. Permitted Vegetated Roof Systems */

2026-07-27T18:02:39Z

‎A-1.1.3.2. Permitted Vegetated Roof Systems

James Klassen: /* A-1.1.3.2. Permitted Vegetated Roof Systems */

2026-07-27T18:01:11Z

‎A-1.1.3.2. Permitted Vegetated Roof Systems

James Klassen: /* A-1.1.3.2. Permitted Vegetated Roof Systems */

2026-07-27T17:59:08Z

‎A-1.1.3.2. Permitted Vegetated Roof Systems

James Klassen: /* A-10.3.2.16. Planting Shrubs and Trees */

2025-04-22T20:55:25Z

‎A-10.3.2.16. Planting Shrubs and Trees

Show changes

@@ Line 127: / Line 127: @@
 </div>
-:::<small>(*) ''Vegetation'' support refers to growing media which may be homogeneous or stratified, depending on overall depth.  Ranges shown in the table are typical.  For more about what is permissible, see [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] in the "RGC Standard for Vegetated Roofs".</small>
+:::<small>* ''Vegetation'' support refers to growing media which may be homogeneous or stratified, depending on overall depth.  Ranges shown in the table are typical.<br>For more about what is permissible and what limits coverage under a '''''RoofStar Vegetated Roof Guarantee''''', see [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] in the "RGC Standard for Vegetated Roofs".</small>
-:::<small>(**) Maintenance costs will also be driven by roof accessibility and continuity or discontinuity between roof areas.</small>
+:::<small>** Maintenance costs will also be driven by roof accessibility and continuity or discontinuity between roof areas.</small>
-:::<small>(†) ''Growing media'' saturation weights in '''Table A-1.1.3.2.''' are adapted from the "Green Roof Installation and Maintenance Professional Resource Manual", developed jointly by the RCABC and Green Roofs for Healthy Cities, 2022.</small>
+:::<small><sup>†</sup> ''Growing media'' saturation weights in '''Table A-1.1.3.2.''' are adapted from the "Green Roof Installation and Maintenance Professional Resource Manual",<br>developed jointly by the RCABC and Green Roofs for Healthy Cities, 2022.</small>
-:::<small>(††) ''Plant'' diversity refers to genera and, within that, variety in species and habit.  For example, an ''extensive green roof'' is typified by few genera.  By contrast, an ''intensive green roof'' may be typified by a wide variety of genera, and within each genus, a wide range of species.</small>
+:::<small><sup>††</sup> ''Plant'' diversity refers to genera and, within that, variety in species and habit.  For example, an ''extensive green roof'' is typified by few genera.  By contrast, an ''intensive green roof''<br>may be typified by a wide variety of genera, and within each genus, a wide range of species.</small>
 As stated in the Preface to this Standard, this document is “focused on the basics of design and constructability of ''green roofs'' as rainwater management tools, each design (specifically, those that are classified as ''semi-intensive'' or ''intensive'') should aim to balance the limitations of ''vegetation'' on a roof with a diversity of ''plants'', and their appropriate support (''growing media''), to mimic naturally biodiverse habitats.”  A ''green roof'' that includes a diverse range of ''plant'' types (including sizes) provides necessary habitat for a diverse range of insects, birds, and other fauna, and may by virtue of its biodiversity reduce certain maintenance requirements by repelling undesirable ''plant'' species.  Furthermore, some research shows that biodiversity may be a key strategy for moderating climate change; this can not only benefit those who own or occupy the building beneath it but may also add benefits to the wider community.  For more on the subject of biodiversity, refer to the FLL Standard, p. 62, and resources published in the [https://greenroofs.org/living-architecture-monitor Living Architecture Monitor] (including the article, [https://livingarchitecturemonitor.com/articles/art-and-science-of-maintaining-biodiverse-green-roofs-su23 “The Art and Science of Maintaining Biodiverse Green Roofs”], Summer 2022).

@@ Line 78: / Line 78: @@
 ''Vegetated roof systems'' are classified in this Standard by one of three categories: (1) ''Extensive'', (2) ''Semi-intensive'', and (3) ''Intensive''.  '''Table A-1.1.3.2.''' below, adapted from the “Green Roof Installation and Maintenance Professional Resource Manual” (GRHC and RCABC, 2022), sets out the basic criteria of each.  Note that while there are overlapping ranges in system depth, depth is only one criterion that distinguishes one system type from the others.
-'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' with a depth as little as 63.5 mm (2-1/2") (See the limitations in [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] of the "RGC Standard for Vegetated Roofs") but usually ranging from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
+'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' with a depth as little as 63.5 mm (2-1/2") (See the limitations in [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] of the "RGC Standard for Vegetated Roofs") but usually ranging from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth.  Extensive systems also typically consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
 ''Extensive green roof systems'' are generally self-sustaining and evolving, using ''plants'' that tend to conserve water (drought resistant) and are especially adapted to extreme site conditions (FLL 2018, p. 22).  These plants typically require a relatively short period of time for establishment and therefore are suitable for establishing a vegetated profile that can eventually morph into a more varied system.
@@ Line 127: / Line 127: @@
 </div>
-:::<small>(*) ''Vegetation'' support refers to growing media which may be homogeneous or stratified, depending on overall depth (See [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]])</small>
+:::<small>(*) ''Vegetation'' support refers to growing media which may be homogeneous or stratified, depending on overall depth.  Ranges shown in the table are typical.  For more about what is permissible, see [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] in the "RGC Standard for Vegetated Roofs".</small>
 :::<small>(**) Maintenance costs will also be driven by roof accessibility and continuity or discontinuity between roof areas.</small>
 :::<small>(†) ''Growing media'' saturation weights in '''Table A-1.1.3.2.''' are adapted from the "Green Roof Installation and Maintenance Professional Resource Manual", developed jointly by the RCABC and Green Roofs for Healthy Cities, 2022.</small>

@@ Line 78: / Line 78: @@
 ''Vegetated roof systems'' are classified in this Standard by one of three categories: (1) ''Extensive'', (2) ''Semi-intensive'', and (3) ''Intensive''.  '''Table A-1.1.3.2.''' below, adapted from the “Green Roof Installation and Maintenance Professional Resource Manual” (GRHC and RCABC, 2022), sets out the basic criteria of each.  Note that while there are overlapping ranges in system depth, depth is only one criterion that distinguishes one system type from the others.
-'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' as little as 63.5 mm (2-1/2") (See the limitations in [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] of the RGC Standard for Vegetated Roofs) but generally range from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
+'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' with a depth as little as 63.5 mm (2-1/2") (See the limitations in [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] of the "RGC Standard for Vegetated Roofs") but usually ranging from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
 ''Extensive green roof systems'' are generally self-sustaining and evolving, using ''plants'' that tend to conserve water (drought resistant) and are especially adapted to extreme site conditions (FLL 2018, p. 22).  These plants typically require a relatively short period of time for establishment and therefore are suitable for establishing a vegetated profile that can eventually morph into a more varied system.

@@ Line 78: / Line 78: @@
 ''Vegetated roof systems'' are classified in this Standard by one of three categories: (1) ''Extensive'', (2) ''Semi-intensive'', and (3) ''Intensive''.  '''Table A-1.1.3.2.''' below, adapted from the “Green Roof Installation and Maintenance Professional Resource Manual” (GRHC and RCABC, 2022), sets out the basic criteria of each.  Note that while there are overlapping ranges in system depth, depth is only one criterion that distinguishes one system type from the others.
-'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' as little as 63.5 mm (2-1/2") (See the limitations in [[#VRA_Standard#7.1.5.1._Growing_Media_Depth_Requirements_for_All_Assemblies | Article 7.1.5.1.]] of the RGC Standard for Vegetated Roofs) but generally range from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
+'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' as little as 63.5 mm (2-1/2") (See the limitations in [[VRA Standard#7.1.5.1. Growing Media Depth Requirements for All Assemblies | Article 7.1.5.1.]] of the RGC Standard for Vegetated Roofs) but generally range from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
 ''Extensive green roof systems'' are generally self-sustaining and evolving, using ''plants'' that tend to conserve water (drought resistant) and are especially adapted to extreme site conditions (FLL 2018, p. 22).  These plants typically require a relatively short period of time for establishment and therefore are suitable for establishing a vegetated profile that can eventually morph into a more varied system.

@@ Line 78: / Line 78: @@
 ''Vegetated roof systems'' are classified in this Standard by one of three categories: (1) ''Extensive'', (2) ''Semi-intensive'', and (3) ''Intensive''.  '''Table A-1.1.3.2.''' below, adapted from the “Green Roof Installation and Maintenance Professional Resource Manual” (GRHC and RCABC, 2022), sets out the basic criteria of each.  Note that while there are overlapping ranges in system depth, depth is only one criterion that distinguishes one system type from the others.
-'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' support ranging from a minimum of 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
+'''''Extensive green roof systems''''' are typically installed and maintained without the use of penetrating hand tools.  They are commonly constructed on a shallow ''growing media'' as little as 63.5 mm (2-1/2") (See the limitations in [[#VRA_Standard#7.1.5.1._Growing_Media_Depth_Requirements_for_All_Assemblies | Article 7.1.5.1.]] of the RGC Standard for Vegetated Roofs) but generally range from 152.4 mm (6”) to a generally accepted maximum 203.2 mm (8”) in depth, consist of plants commonly referred to as “ornamental” or “succulents” that are selected from only a few genera (i.e., Sedum, Allium, Sempervivum, Euphorbia, and Delosperma), and are often constructed with pre-grown trays, boxes, or mats (sometimes referred to as ‘modular’).  Irrigation is often used primarily to establish the plants, although these plants may require periodic irrigation during extremely dry periods.  Plants in an ''extensive green roof'' are commonly well suited to coping with extreme weather conditions and have the ability to regenerate easily.  Some of these plants may be native to the region for which the ''green roof system'' is designed, though indigeneity is not required or necessarily advisable, especially where ''plant'' roots may be aggressive and hazardous to the supporting ''roof assembly''.
 ''Extensive green roof systems'' are generally self-sustaining and evolving, using ''plants'' that tend to conserve water (drought resistant) and are especially adapted to extreme site conditions (FLL 2018, p. 22).  These plants typically require a relatively short period of time for establishment and therefore are suitable for establishing a vegetated profile that can eventually morph into a more varied system.