Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Vegetated (Green) Roofing
…217 unchanged lines
### The standard assembly shall be limited to roof slopes at or below 15% (8.5°) per ASTM E2777.
−### Slopes between 15% and 33% shall incorporate anti-erosion measures and substrate anchors to prevent down-slope migration of the growing medium.
−
−### The plant palette shall be selected for the roof microclimate, accounting for high heat, wind exposure, and reflected UV from adjacent walls, per ASTM E2400.
−
−### Specifying species unsuited to the roof microclimate is a leading cause of plant failure, and because plant loss triggers warranty inspections that route back to the waterproofer, palette selection is a waterproofing-warranty concern, not only a horticultural one. {note}
−
```datasheet
label: Maximum Roof Slope
…6 unchanged lines
```
+### Slopes between 15% and 33% shall incorporate anti-erosion measures and substrate anchors to prevent down-slope migration of the growing medium.
+
+### The plant palette shall be selected for the roof microclimate, accounting for high heat, wind exposure, and reflected UV from adjacent walls, per ASTM E2400.
+
+### Specifying species unsuited to the roof microclimate is a leading cause of plant failure, and because plant loss triggers warranty inspections that route back to the waterproofer, palette selection is a waterproofing-warranty concern, not only a horticultural one. {note}
+
# Waterproofing Root Resistance and Protection {toc}
…47 unchanged lines
### An electronic leak-detection survey (Electronic Field Vector Mapping, EFVM) per ASTM D7877 shall be performed both before overburden installation and after the assembly is complete where the vegetated roof is over occupied space.
−### Over occupied space, leak detection is not optional: once overburden is placed, a leak cannot be located without removing the assembly above it, so a before-and-after electronic survey is the only practical safeguard against tearing out a planted roof to find a pinhole. {note}
−
```datasheet
label: Leak-Detection Method
…6 unchanged lines
```
+### Over occupied space, leak detection is not optional: once overburden is placed, a leak cannot be located without removing the assembly above it, so a before-and-after electronic survey is the only practical safeguard against tearing out a planted roof to find a pinhole. {note}
+
# Drainage and Retention Layer {toc}
−## A drainage and retention layer shall be installed above the protection layer to convey excess water to the roof drains while retaining water for plant use. {note}
+## A drainage and retention layer shall be installed above the protection layer to convey excess water to the roof drains while retaining water for plant use.
−## The drainage layer is the hydraulic core of the assembly: it must shed water fast enough to prevent the growing medium from becoming saturated and overloaded, while retaining enough moisture between rain events to sustain the plants. These two demands are met by aggregate, by prefabricated drainage composites, or by modular trays with an integral reservoir. {note}
−
−## The hydraulic conductivity of the drainage layer shall exceed that of the growing medium and shall be not less than 0.02 in./sec (approximately 50 mm/min).
−
−## Granular drainage media, where specified, shall be qualified for saturated water permeability per ASTM E2396.
−
−## A filter fabric shall separate the growing medium from the drainage layer to prevent fines from migrating into and clogging the drainage course.
−
−## Sizing the assembly without checking that the drainage layer is more permeable than the growing medium inverts the design: water then perches in the medium, raising the saturated weight and drowning roots. The conductivity check is the single most important hydraulic verification in the assembly. {note}
−
```datasheet
label: Drainage / Retention Layer Type
…7 unchanged lines
```
+## The drainage layer is the hydraulic core of the assembly: it must shed water fast enough to prevent the growing medium from becoming saturated and overloaded, while retaining enough moisture between rain events to sustain the plants. These two demands are met by aggregate, by prefabricated drainage composites, or by modular trays with an integral reservoir. {note}
+
+## The hydraulic conductivity of the drainage layer shall exceed that of the growing medium and shall be not less than 0.02 in./sec (approximately 50 mm/min).
+
```datasheet
label: Minimum Drainage Layer Hydraulic Conductivity
…6 unchanged lines
```
+## Granular drainage media, where specified, shall be qualified for saturated water permeability per ASTM E2396.
+
+## A filter fabric shall separate the growing medium from the drainage layer to prevent fines from migrating into and clogging the drainage course.
+
```datasheet
label: Filter Fabric Between Medium and Drainage
…5 unchanged lines
```
+## Sizing the assembly without checking that the drainage layer is more permeable than the growing medium inverts the design: water then perches in the medium, raising the saturated weight and drowning roots. The conductivity check is the single most important hydraulic verification in the assembly. {note}
+
# Growing Medium {toc}
−## The growing medium shall be an engineered mineral blend, not natural topsoil or compost-heavy garden soil. {note}
+## The growing medium shall be an engineered mineral blend, not natural topsoil or compost-heavy garden soil.
## Engineered green-roof medium is dominated by lightweight mineral aggregate - expanded shale, clay, or slate (ESCS), pumice, or crushed lava - amended with a limited fraction of organic matter. Topsoil and compost-rich mixes are forbidden because they are heavy when saturated, settle severely as the organics decompose, and drift in pH over time. {note}
…78 unchanged lines
# Irrigation {toc}
−## The irrigation strategy shall match the assembly type: none for established drought-tolerant extensive assemblies, temporary establishment-only drip for marginal extensive and semi-intensive assemblies, and permanent drip or spray for intensive and occupied decks. {note}
+## The irrigation strategy shall match the assembly type: none for established drought-tolerant extensive assemblies, temporary establishment-only drip for marginal extensive and semi-intensive assemblies, and permanent drip or spray for intensive and occupied decks.
## Where any irrigation is provided, the system shall include backflow prevention in accordance with the plumbing code and a drainage outlet that discharges to the roof drainage system.
…20 unchanged lines
### A perimeter ballast strip or equivalent wind-uplift anchor zone, not less than 4 in. wide of washed aggregate or pavers, shall be provided at roof edges and around penetrations.
+```datasheet
+label: Perimeter Ballast Strip Width
+type: range
+unit: in
+min: 4
+max: 24
+step: 1
+default: 12
+```
+
### Edge restraint shall retain the growing medium and drainage layer at all free edges, drains, and penetrations, by ballasted gravel strip, concrete pavers, or mechanical edge clips as required by the wind design.
−### Omitting a perimeter ballast or anchor zone at edges and penetrations violates ANSI/SPRI RP-14 and creates a foreign-object-debris hazard, because the unballasted perimeter is exactly where uplift scours loose medium and lightweight components off the roof. {note}
−
```datasheet
label: Perimeter / Penetration Edge Restraint
…6 unchanged lines
```
−```datasheet
−label: Perimeter Ballast Strip Width
−type: range
−unit: in
−min: 4
−max: 24
−step: 1
−default: 12
−```
+### Omitting a perimeter ballast or anchor zone at edges and penetrations violates ANSI/SPRI RP-14 and creates a foreign-object-debris hazard, because the unballasted perimeter is exactly where uplift scours loose medium and lightweight components off the roof. {note}
## Fire Resistance {toc}
### The vegetated roof assembly shall achieve a fire-spread classification per ANSI/SPRI VF-1-2023, as required by IBC 2021 Section 1507.16, for the specific membrane, growing-medium depth, and plant species actually specified.
−### The fire classification applies to the assembly as a tested combination. A Class A rating earned by one membrane and sedum mix does not transfer to a different membrane, a deeper medium, or a taller plant palette - the submitted assembly must name the tested combination that matches the construction. {note}
−
−### Wood blocking, curbs, and nailers in contact with the vegetated assembly shall be fire-retardant-treated (FRT) lumber in accordance with IBC 2021 Section 1507.16.
−
−### Substituting standard untreated blocking at curbs and nailers is a code violation, not merely a durability concern, because IBC 1507.16 explicitly requires FRT lumber where wood contacts the vegetated assembly. {note}
−
```datasheet
label: Required Fire Classification (ANSI/SPRI VF-1)
…6 unchanged lines
```
+### The fire classification applies to the assembly as a tested combination. A Class A rating earned by one membrane and sedum mix does not transfer to a different membrane, a deeper medium, or a taller plant palette - the submitted assembly must name the tested combination that matches the construction. {note}
+
+### Wood blocking, curbs, and nailers in contact with the vegetated assembly shall be fire-retardant-treated (FRT) lumber in accordance with IBC 2021 Section 1507.16.
+
```datasheet
label: Wood Blocking / Curbs at Assembly
…5 unchanged lines
```
+### Substituting standard untreated blocking at curbs and nailers is a code violation, not merely a durability concern, because IBC 1507.16 explicitly requires FRT lumber where wood contacts the vegetated assembly. {note}
+
# Drainage Coordination at Drains and Overflows {toc}
## Roof drains, scuppers, and overflows shall be sized and set to account for the added flow resistance of the growing medium and drainage layer, and shall remain accessible for inspection through the overburden.
−## A vegetated roof slows peak runoff, which is its purpose, but during extreme events the assembly can surcharge the drains; overflow and scupper invert elevations must be set above the assembly depth so the roof can shed water before it ponds onto the medium. {note}
+## A vegetated roof slows peak runoff, which is its purpose, but during extreme events the assembly can surcharge the drains; overflow and scupper invert elevations must be set above the assembly depth so the roof can shed water before it ponds onto the medium.
## Drain locations, scupper and overflow elevations, and inspection-chamber locations are arrangement decisions fixed by the roof plan and shall be taken from the drawings: [[drawing: roof drain and overflow plan]].
…80 unchanged lines
- Reserve plant material (matching species)
```