Template:Part 11 (Waterproofing Roofs - Singleply)

1 General

This section pertains to the waterproofing of roof penetrations, curbs, sleepers, drains and any other "details", in order to qualify for a RoofStar Guarantee.

1.1 Definitions

Refer to the Glossary for further definitions of key terms used in this Manual.

Roof Drain: means “A fitting or device that is installed in the roof to permit storm water to discharge into a leader.” (British Columbia Plumbing Code, Division A, Part 1).
Drain Leader: means "a pipe that is installed to carry storm water from a roof to a storm building drain or sewer or other place of disposal” (British Columbia Plumbing Code, Division A, Part 1).
Primary Roof Drain: means the primary means of draining water from the roof.
Secondary Roof Drain: means an alternate drainage path in the event of large rain events or significant snow melt, typically situated at a higher elevation than a primary roof drain.
Scupper Drain: means an open or closed roof drain that conveys water laterally from one roof area to another, or from the roof directly to the exterior of the building.
Overflow Drain: means a secondary roof drain that serves as a safeguard when roof drains fail. An overflow may be located in the roof field (for example, as a secondary drain) or at the perimeter of the roof.
Flange-style Drain: means a primary roof drain with a flat, broad flange fabricated from the same material as the bowl and leader, and encompassing the perimeter of the drain bowl or, in the case of flat drains, the drain leader. Flange-style drains are not cast but rather are manufactured from components that are hot-welded. Flange-style drains are typically secured to the roof with mechanical fasteners.

1.2 Design (Drainage)

1.2.1 RoofStar 15-Year Guarantee

Refer to 1.3.1 RoofStar 15-Year Guarantee for general requirements, to qualify the Project for a RoofStar 15-year Guarantee.
All roof areas must be designed with overflow drains that are properly sized and spaced, in keeping with the building and plumbing codes having jurisdiction.

1.2.2 All Projects

With the exception of overflows, scupper drains and membrane gutters, roof drains and penetration flashings for new construction Projects must be located at least 300 mm (12”) away from any adjacent drain, penetration, upstand, edge or wall. The separation space is measured between openings, excluding the flange.
When existing roof drain and penetration locations do not comply with the Standards above, a Variance must be requested from the RoofStar Guarantee Program, and accompanied by plan and detail drawings to show how the Guarantee Standards will be met by the design and construction.
Only cast-iron roof drains, and existing external couplers used to connect drains to leaders, may be re-used for roof replacement Projects. All flange-style drains, scuppers and overflows, together with internal drain-to-pipe compression seals, and seals exposed to water or ultraviolet light, must be replaced.
All penetration flashings must be replaced in a roof replacement Project.
The Design Authority is responsible for the design of roof drainage. The size (flow rate) of roof drains and overflows should be determined through the British Columbia Building Code and British Columbia Plumbing Code, with attention given to both average and large rainfall events. For rainfall capacities, refer to the British Columbia Building Code, Div. B, Appendix C, Table C-2 which lists rainfall loads using specific reference locations throughout the province. The RGC recommends that various disciplines, including but not limited to mechanical (plumbing) and structural engineers, coordinate calculations to ensure proper flow rates, head pressure and structural supports, in anticipation of significant, short-duration rain events. Consideration should be given to the following elements (without limitation):
1. Roof slope – more slope theoretically increases drainage and lessens live loading from rainfall (see also 2.2 Roof Slope).
2. Rainfall rates for primary and overflow drainage.
3. Primary and overflow drain capacities.
4. Hydraulic head (pressure).
Roof drains must not be used as a conduit for other services, such as electrical. All other services must be designed to utilize separate penetration points with purpose-made penetration flashings and Guarantee-compliant detailing.
Roofs may drain off a roof edge or by means of internal plumbing. Both are permissible under the RoofStar Guarantee Program.
When a roof is designed to drain off an edge, water may drain freely or be collected by means of an external or built-in gutter (12.2 Built-in Membrane Gutters) and drained onto a lower roof assembly. The membrane on the lower roof must be protected from abrasion with splash pads.
When roofs are designed to drain through internal plumbing, the following standards, guiding principles and recommendations apply.
1. Drain sumps should be incorporated into a roof design whenever possible, to increase head pressure above primary roof drains. Drain sumps should be designed at least 1m x 1m (39” x 39”) in size. The depth of a sump is a function of insulation thickness (see 7.1.2.10). Sumps designed with sloped insulation are strongly recommended.
2. New and existing buildings should incorporate overflows to handle large rain events. The primary function of an overflow is to keep a roof from collapsing when primary roof drains are plugged or cannot drain heavy rainfall. Where no overflows are specified, the building structure should be designed to carry the total load of water collected on the roof, in the event of the failure of roof drains (see British Columbia Building Code).
3. When overflows are specified, they must be
  1. located
    1. no higher than 100 mm (4”) above drain elevations.
    2. so that they visibly discharge storm water.
  2. designed with an opening sufficient in size to equal or exceed the rate of rainfall.
  3. designed as open-wall scuppers for parapets measuring 150 mm (6”) or less in height.
  4. designed around the principles of a through-wall scupper, for parapets higher than 150 mm (6”).
4. Overflows must incorporate a continuous flange surrounding the drain opening, measuring at least 100 mm (4”) in width, and may be manufactured from ferrous metals, subject to the Material standards for metal found in this Manual.
5. Overflows are required for low doorway or low window details. In these applications, the overflow must be installed at least 1” lower than the lowest elevation of the door or window opening.
6. A scupper drain may serve either as a primary roof drain or as a secondary drain.
All drains located at the water plane must be fully blocked above the supporting deck structure.
If a flow restrictor is present in an existing cast drain leader, the restrictor should be reinstalled.
Drain extensions for cast-iron roof drains should be avoided, since the connection with the cast drain is not sealed; the result is a leak into the roof system.
Roofs that support overburden or are secured with ballast must be designed to incorporate a ballast guard that surrounds the drain and promotes unrestricted flow.

1.3 Design (Curbs and Penetrations)

1.3.1 RoofStar 15-Year Guarantee

Refer to 1.3.1 RoofStar 15-Year Guarantee for general requirements, to qualify the Project for a RoofStar 15-year Guarantee.
When a roof is replaced, all penetration flashings that do not utilize a fitted cap must be installed with clamped double storm collars that are fully sealed around the upper edge. For roofs on newly constructed buildings, the Contractor is responsible to supply and install a second storm collar around the penetration (the first collar is typically supplied and installed by others).
All electrical, gas and other services that penetrate the roof assembly must be protected against water intrusion with
1. proprietary flashings that are sealed into the roof system.
2. curbs fitted with a “weather head” hood sealed into the curb membrane flashing.
3. sealant pockets (used only where unavoidable) that comply with the RoofStar 15-year Guarantee Standards found in 11.3 Application.

1.3.2 All Projects

Roof openings must be enclosed and sealed
1. with curbs.
2. penetration flashings.
Except where fully enveloped sleepers are incorporated in the design, all membrane flashing (stripping) must extend vertically on perimeter surfaces at least 200 mm (8") above the roof field membrane, to permit a proper watertight seal. Where pavers, ballast, growing media or any other type of Roof Coverings are designed for placement on top of the field membrane, both membrane flashing and purpose-made penetration flashings must be carried vertically past the top surface of the covering (the Finished Roof Assembly) at least 200 mm (8”) (see 11.1.2.1 Drainage; see also 11.3.2.5 Scuppers and Overflows).
Curbs and metal-flanged roof penetrations (i.e. drains and B-vents) must be firmly supported directly on the deck structure or with blocking, and must not be unsupported on top of the roof system.
Galvanized flashings and vents
1. are permitted on uninsulated or conventionally insulated assemblies, provided the penetration opening does not exceed 0.126 m² (196 in²) and it is field-wrapped with the roof membrane. Non-proprietary membrane-compatible coated flashings are not permissible.
2. are not permitted at the water plane in a Protected or Modified Protected Membrane Roof Assembly. Instead, the penetration must be enclosed by a curb measuring at least 200 mm (8") in height above the finished roof surface; the galvanized or welded flashing may then be installed, field-wrapped with the roof membrane, and flashed in on top of the curb.
3. larger than 0.126 m² (196 in²) must be enclosed or supported by a curb.
Aluminum or copper flashings for penetrations may be located at the water plane in any assembly type.
Roof penetration flashings must be
1. suitable for only one penetration.
2. properly fitted to form a seal around the penetration.
Where a standard flashing is not tall enough to enclose and seal the penetration, the joint between the penetration and the flashing must be sealed with alternative methods.
Sleepers or equipment pads that are completely sealed (enveloped) must be at least 100 mm (4") in height above the finished roof surface, but when they are capped with a metal flashing they must be at least 125 mm (5") in height. All penetrations through the top surface of a sleeper or equipment pad must be additionally sealed.
Housekeeping pads situated on top of the finished roof surface and supporting a combined load less than 90 kg (200 lbs) must be separated from the roof with a bond-breaking layer (i.e. XPS insulation) Housekeeping pads supporting larger loads must conform to the standards for sleepers or equipment pads. A separation layer between XPS insulation and PVC membranes is required, to prevent leaching of plasticizers from the field membrane.
When mechanical equipment that is ventilated on the roof extracts and discharges grease, chemicals or other contaminants that may adversely impact the roof membrane or other system components, the Design Authority should specify additional protection measures (for example, grease guards or a proprietary liquid membrane coating).
Guardrails should be designed for attachment on vertical surfaces only; attachment of guardrails to a horizontal surface is strongly discouraged.
Pourable sealant pockets should be used only as a last resort, when other flashing methods are impractical. See also 11.3.3.4 Sealant Pockets for Application requirements.

2 Materials

2.1 General

Only new drains and penetration flashings listed in this Manual may be used on a Project designed and constructed to qualify for a RoofStar Guarantee. Reuse of any existing drain (with the exception of serviceable cast iron drains) or any penetration flashing is prohibited and may void the Guarantee. See also 1.6 RoofStar Guarantee: Coverage and Limitations.
All proprietary membrane flashing accessories used to flash penetrations must be manufactured and supplied by the manufacturer of the primary roof membrane.

2.2 Roof Drains and Scuppers

Roof drains are comprised mainly of two parts: a bowl or flange that is affixed to the roof deck with mechanical fasteners or a proprietary clamping mechanism; and an integral drain stem that connects the bowl or flange to the leader. Roof drains are sized according to the diameter of the drain stem. As stated above under Design, the appropriate size and number of roof drains for any given roof area is determined by the relevant building code in force (ref. British Columbia Plumbing Code, Division B – Part 2; 2.4.10.4 Hydraulic Loads from Roofs or Paved Surfaces).

Roof drains can be further classified as internal or external. Internal roof drains are connected to leaders located and connected to a storm building drain or sewer inside the exterior surface of a building. Internal roof drains may be made of cast iron (secured to the roof assembly with clamps) or from copper or aluminum, fashioned from spun components that are welded together and incorporate a flange around the drain bowl. External roof drains direct storm water outside the exterior surface of a building. Scuppers and overflow drains are the common types of external roof drains, and may connect to leaders or simply drain freely. Any requirements for leaders and connections to leaders may be found in the applicable municipal and provincial building and plumbing codes (ref. British Columbia Building Code, 5.6.2.2 Accumulation and Disposal).

All flange-style drains must be manufactured with a hot-welded or seamless flange at least 100 mm (4”) wide when measured from the outer edge of the drain opening.
Cast-iron Roof Drains must be
1. supplied with a sump receiver and under-deck clamp.
2. installed by the trade supplying the roof drain.
Internal flange-type roof drains must be
1. hot-welded at the joints between the bowl/flange and drain stem.
2. equipped with a membrane clamping ring.
3. equipped with secured strainers.
4. constructed of non-ferrous material:
  1. Copper drains for internal application shall be formed from a minimum weight of 24 oz. sheet copper (0.55 mm or 0.0216”).
  2. Aluminum drains for internal application shall be formed from a minimum of 12 gauge material (0.820 mm or 0.0325”).
External flange-type roof drains must be hot-welded at the joints between the bowl/flange and drain stem and shall be constructed of non-ferrous material:
1. Copper drains for external application shall be formed from a minimum weight of 16 oz. (0.55 mm or 0.0216”).
2. Aluminum drains for external application shall be formed from a minimum of 20 gauge material (0.81 mm or 0.032”).
Only mechanical compression type seals may be used to connect insert-type drains to internal drain leaders.
Scupper drains (open or closed) must be
1. manufactured with welded seams and joints.
2. fabricated from
  1. copper with a minimum weight of 16 oz. (0.55 mm or 0.0216”).
  2. aluminum with a minimum thickness of 20 gauge (0.812 mm or 0.032”).
3. fabricated with a continuous flange surrounding the drain opening, measuring at least 100 mm (4”) in width.
4. designed to extend past the outside face of the wall.
Closed (boxed) scupper drains must be
1. fabricated from
  1. copper with a minimum weight of 16 oz. (0.55 mm or 0.0216”).
  2. aluminum with a minimum thickness of 20 gauge (0.812 mm or 0.032”).
2. fully enclosed on four sides, for through-wall applications.
3. fitted with an overflow opening at the outside face
  1. equal in capacity to the main drain leader opening.
  2. at least 38 mm (1 ½”) lower than the top surface of the scupper drain.
4. fabricated with a drip edge at the bottom outside edge of the drain to deflect overflow water away from the building.
Overflow drains must incorporate a continuous flange surrounding the drain opening, measuring at least 100 mm (4”) in width, and may be manufactured from ferrous metals, subject to the Material standards for metal found in this Manual. Pipe-styled overflow drains must be welded at the flange.
All roof drains utilized in a roof assembly that includes gravel ballast or growing media (soil) must be supplied with the drain manufacturer's proprietary primary drain strainer and secondary stainless steel ballast guard. In the absence of a proprietary ballast guard, a custom-fabricated guard may be used provided it meets the following requirements:
1. Fabricated from 20-gauge stainless steel.
2. Incorporates 6 mm (1/4”) perforations.
3. Equal to or greater in height than the top of the finished roof assembly.

2.3 Curbs and Penetration Flashings

All membrane-flashed roof flashings for cylindrical penetrations must be manufactured with materials and methods that meet or exceed the requirements set out in CSA B272, Prefabricated Self-Sealing Roof Vent Flashings. Testing by a qualified third party is required to verify compliance with this standard.
Notwithstanding the above, all penetration flashings must be
1. watertight and seamless or, in the alternative, fabricated with fully hot-welded joints.
2. at least 8" in height, from the flange to the opening or top of the flashing.
3. fabricated with a hot-welded or seamless flange at least 100 mm (4") wide, around the bottom of the flashing.
4. fabricated with a tightly fitted or mechanically attached settlement cap or lid (if so required).
Galvanized flashings and vents must
1. meet or exceed the CSA A93 Standard.
2. be made with material no less than 26 Ga. galvanized steel conforming to the metal standards found in 13 METAL FLASHINGS of this Manual.
3. be field-wrapped with the roof membrane. Non-proprietary membrane-compatible coated flashings are not permissible.
Single or multiple penetrations may not be flashed with an open-topped flashing filled with sealant, but must be sealed into the roof assembly with one of the following options:
1. Electrical cable penetrations must utilize a gooseneck-type flashing with a weather hood.
2. Pipe-type penetrations must be sealed with
  1. the manufacturer’s proprietary rubber-based friction seals, mechanical clamps or gooseneck type design.
  2. a 2-part site-fabricated or proprietary flashing with a removable inspection/access cap.
  3. roof curbs and customized metal hoods.
Penetration flashings should be selected for their ability to inhibit the intrusion of vermin and insects into the roof assembly and building interior.

2.4 Fasteners

Mechanical fasteners used to secure the roof membrane and penetration flashings or related accessories must be
1. properly sized in accordance with roof system securement requirements (see 3 SECURING the ROOF ASSEMBLY).
2. self-drilling purpose-made screws having a deep-recessed head.

2.5 Sealants

Sealants must be manufactured by or acceptable to the membrane manufacturer.
Compression sealants must be formulated to provide waterproofed seals under compressive loads.

3 Application

3.1 General

3.1.1 RoofStar 15-Year Guarantee

Refer to 11.1.2.2 and 11.1.3.1 for requirements to qualify for a RoofStar 15-Year Guarantee.
All outside corners on EPDM membrane system Projects must be double-wrapped using semi-cured membrane, installed according to the membrane manufacturer’s published details and written requirements.
All electrical, gas and other services that penetrate the roof assembly must be protected against water intrusion with
1. proprietary flashings that are sealed into the roof system.
2. curbs fitted with a “weather head” hood sealed into the curb membrane flashing.
3. sealant pockets (used only where unavoidable) that, in addition to the Standards in 11.3.3.4 Sealant Pockets, are at least 100 mm (4”) tall, or elevated the same distance above the water plane, when measured from the water plane to the top of the pocket.

3.1.2 All Projects

With the exception of overflows, scupper drains and membrane gutters, roof drains and penetration flashings for new construction Projects must be located at least 300 mm (12”) away from any adjacent drain, penetration, upstand, edge or wall. The separation space is measured between openings, excluding the flange.
Blocking installed to support drains or protrusion flashings (normally the work of other trades) must be sufficiently secured to the supporting deck to resist wind uplift loads.
All membrane flashing must be hand rolled with a membrane manufacturer’s accepted roller.
All inside and outside corners of membrane-flashed penetrations must be reinforced with the membrane manufacturer’s proprietary membrane gussets or corners (pre-formed or site-fabricated), measuring at least 150 mm x 150 mm (6” x 6”), unless exceeded by the membrane manufacturer’s published requirements.
All seams, gussets, corners and membrane covers must be properly prepared and sealed at the edges with a membrane-compatible sealant.
All metal flanged penetrations must be
1. clean and dry.
2. rounded (trimmed) at the corners.
3. separated from wood blocking with a membrane separation sheet.
4. installed in a bed of sealant acceptable to the membrane manufacturer.
5. securely fastened to wood blocking.
Membrane patches installed over flanged drains or penetration flashings must be
1. of like kind and thickness as the field membrane, unless otherwise specified by a manufacturer’s detail.
2. large enough to extend past the flange
  1. at least 75 mm (3”), and fully adhered to the field membrane (EPDM only).
  2. hot-welded to the field membrane along the outer 50 mm (2”) perimeter of the patch and sealed along the edges of the patch with a compatible sealant (TPO and PVC only).
3. extended up any vertical surface at least 200 mm (8”) and clamped (where required in these Standards).
4. sealed at all edges with an acceptable sealant.

3.2 Roof Drains

3.2.1 General

Drains must be secured to the supporting deck structure, or to blocking.
All insert-type drains shall be connected to internal leaders using only mechanical compression type seals. “O”- rings, mastics and caulking are not acceptable methods for sealing these types of drains to leaders.
Proprietary water-compression sealant must be used on all drain applications.
All clamping rings and strainers must be unbroken, properly seated and fully secured.
When a roof supports overburden or is secured with ballast, drains must be installed together with a surrounding ballast guard that promotes unrestricted flow. This requirement is in addition to the requirement for a separation space required for Vegetated Roof Systems. See also 14.1.2.2.3(6).
When a membrane field seam comes within 150 mm (6”) of the drain clamping ring or a drain sump, the roof drain or sump must be separately flashed with a target patch
1. symmetrical in size and centred over the drain.
2. cut from the same material as the field membrane.
3. installed before the field membrane, to achieve positive membrane laps.
4. extending past the cut field membrane a sufficient distance for the required seam (see 9.3.1.2 All Projects).

3.2.2 Cast-iron Roof Drains

When cast-iron roof drains are used, a sump receiver and under-deck clamp must be provided and installed by the trade supplying the roof drain.
Drain extensions for cast-iron roof drains should be avoided.
Notwithstanding the above, if a flow restrictor is present in an existing cast drain leader, the restrictor should be reinstalled.
Cast-iron drains installed with continuous field membrane:
1. The continuity of air and vapour control layers must be maintained, where the controls are specified.
2. All roof assembly components, including tapered insulation, must be cut to fit closely around the drain bowl and leader.
3. The drain flange must be clean and dry.
4. A membrane-compatible sealant must be applied to the drain flange where it makes contact with the clamping ring.
5. A membrane patch, matching in thickness and composition to the field membrane, must be
  1. applied over the drain flange and onto the roof field.
  2. cut for the drain opening so that the opening exceeds the size of the drainpipe, but the membrane must extend inside drain bowl at least 12 mm (1/2") past the clamping ring and its attachment points.
  3. punched or tightly cut for clamping bolt holes; clamping ring bolts must be snugly threaded through each hole.
  4. formed to conform to the contours of the drain bowl.
  5. symmetrical and large enough to extend from the clamping ring at least 150 mm (6”) to the edge of the finished seam.
6. The clamping ring must be seated and secured, ensuring it is not broken.
7. The drain screen must be securely installed.
Cast-iron drains installed with membrane flashing (target patch):
1. The continuity of air and vapour control layers must be maintained, where the controls are specified.
2. All roof assembly components, including tapered insulation, must be cut to fit closely around the drain bowl and leader.
3. The drain flange must be clean and dry.
4. A membrane-compatible sealant must be applied to the drain flange where it makes contact with the clamping ring.
5. A membrane patch, matching in thickness and composition to the field membrane, must be
  1. applied over the drain flange and onto the roof field.
  2. cut for the drain opening so that the opening exceeds the size of the drainpipe, but the membrane must extend inside drain bowl at least 12 mm (1/2") past the clamping ring and its attachment points.
  3. punched or tightly cut for clamping bolt holes; clamping ring bolts must be snugly threaded through each hole.
  4. formed to conform to the contours of the drain bowl.
  5. symmetrical and large enough to extend from the clamping ring at least 150 mm (6”) to the edge of the finished seam.
  6. seamed and sealed with the field membrane in keeping with the standards for seams in 9.3.1.2 All Projects.

3.2.3 Roof Drain Inserts (Replacement Roofing)

An external coupling is preferable to an internal mechanical compression seal, but when an internal compression seal is used out of necessity, the joint must be properly prepared to ensure the joined surfaces are clean, smooth and uniform. Honing out the cast pipe may be required.
When a cast-iron roof drain has deteriorated to the extent that it cannot receive a new roof membrane, installation must conform to the membrane manufacturer's published instructions, or to the following standards, whichever are greater:
1. Remove any broken parts and debris.
2. Install the drain insert utilizing a compression seal (see 11.3.2.1 General).
3. Follow the requirements set out in 13.3.2.4 below.

3.2.4 [NOT USED]

3.2.5 Scuppers and Overflows

Open scupper drains may be constructed to match the height of the parapet or roof edge, and must be fully sealed with the field and perimeter membrane flashing.
When a through-wall scupper is specified, only fully enclosed scupper drains (enclosed on all sides and open only at the inflow and outflow ends) may be installed.
Clamping collars must be securely installed as designed and where specified.

3.3 Curbs and Penetration Flashings

3.3.1 General

Roof openings must be enclosed and sealed with either of the following:
1. curbs.
2. penetration flashings.
Curbs and penetration flashings must extend at least 200 mm (8”) above the finished surface of the roof assembly. Waterproofing of equipment installed on a curb is the responsibility of others.
Membrane that terminates on any vertical surface must be secured to the vertical substrate by the Contractor.
Roof penetration flashings designed for a single penetration must
1. be suitable for only a single rigid penetration.
2. be properly fitted to form or permit a seal around the penetration.
3. trimmed to eliminate sharp corners.
4. fully supported from the deck.
5. not be used with multiple pipe roof penetrations.
6. sealed to the penetration with a stainless-steel clamping ring and sealant applied to the membrane edge.
Multiple or flexible penetrations may not be flashed with an open-topped flashing filled with sealant, but must be sealed into the roof assembly with one of the following options:
1. Electrical cable penetrations
  1. must pass through a gooseneck-type flashing with a weather hood.
  2. should be drooped to prevent water ingress through the flashing.
2. Pipe-type penetrations must be sealed with
  1. the manufacturer’s proprietary rubber-based friction seals, mechanical clamps or gooseneck type design.
  2. A 2-part site-fabricated or proprietary retrofit flashing with a removable inspection/access cap.
  3. Roof curbs and customized metal hoods.
Where a purpose-made flashing does not fit the penetration, the joint between the penetration and the flashing must be sealed using one of the following methods:
1. Fit a site-formed non-bituminous flexible roof membrane storm collar and secure it to the flashing and penetration with stainless steel clamps.
2. Apply a shrink-wrapped terminations secured with a stainless steel mechanical compression strap. Regardless of the method, sealant must be applied between the penetration and the collar or shrink-wrapping.
Galvanized, hot-welded flashings and vents may be installed on
1. uninsulated or conventionally-insulated membrane roofs, provided the vents
  1. measure no more than 350 mm x 350 mm (14" x 14") in size, equal to approximately 0.12 meter squared (196 sq. in.) (Larger vents must be installed on curbs).
  2. are not located in or near a valley and are well drained.
2. slopes less than 1:50 (1/4” in 12”), provided the vents are coated on all surfaces to a point at least 100 mm (4") above the finished roof surface with a one or two-part liquid flashing acceptable to the membrane manufacturer.
3. Protected or Modified Protected Membrane Roof Assemblies, provided the vents are mounted on membrane-flashed curbs.
When a pipe-type penetration is flashed with a cylindrical or conical purpose-made metal flashing that does not incorporate a fitted cap, the penetration must be protected immediately above the exposed top of the flashing with at least one properly fitted, level storm collar. All storm collars must be sealed at the top edge with an acceptable sealant. This Standard applies to B-vent penetrations also.
Except where fully enveloped sleepers are utilized, all membrane flashing (stripping) must extend vertically on perimeter surfaces at least 200 mm (8") above the roof field membrane, to permit a proper watertight seal. Where pavers, ballast, growing media or any other type of Roof Coverings are installed on top of the field membrane, both membrane flashing and purpose-made penetration flashings must extend vertically past the top surface of the covering (the Finished Roof Assembly) at least 200 mm (8”)(see 11.1.2 Drainage; see also 11.3.2.5 Scuppers and Overflows)
Sleepers or equipment pads that are completely sealed (enveloped) must be at least 100 mm (4") in height above the finished roof surface, but when they are capped with a metal flashing they must be at least 125 mm (5") in height. All penetrations through the top surface of a sleeper or equipment pad must be additionally sealed using
1. a compression sealant between the membrane and equipment supports.
2. a universal sealant applied around the edges of equipment supports.
Housekeeping pads situated on top of the finished roof surface and supporting a combined load less than 90 kg (200 lbs) must be separated from the roof with a bond-breaking layer (i.e. XPS insulation, or a drainage mat for PVC membranes). Housekeeping pads supporting larger loads must conform to the Standards for sleepers or equipment pads.
Pourable sealant pockets should be used only when a purpose-made flashing is not available or practicable.

3.3.2 [NOT USED]

3.3.3 [NOT USED]

3.3.4 Sealant Pockets

When pourable sealant pockets are considered as the last resort to seal a penetration,
1. the penetration surfaces must be properly prepared following the sealant manufacturer’s instructions, to ensure a good bond between the penetration and the sealant.
2. unless exceeded by the published instructions of the manufacturer, sealant pockets must be
  1. cleaned and primed.
  2. at least 50 mm (2”) deep.
  3. large enough to provide at least 25 mm (1”) of fillable space on all sides of the penetration.
  4. crowned with sealant to shed water.
3. only the membrane manufacturer’s approved proprietary UV-stable urethane-based structural sealants may be used to fill sealant pockets.
4. sealant pockets must be sealed to the roof membrane.
5. a site-formed non-bituminous flexible roof membrane storm collar must be fitted and secure it to the penetration with stainless steel clamps.

3.4 Guardrails

Guardrails should be installed only on vertical surfaces; attachment of guardrails to a horizontal surface is strongly discouraged.
Where guardrails are fastened through the top of copings, the base shall be installed in a continuous bed of compression sealant, but in any event, a written Variance must be requested from the Guarantor.
Guardrails shall not direct water into a roof system by means of weep holes or the method of fastening, and mounts and flashings shall be installed at least 87.7 mm (3 ½”) above the roof surface.

For reference, see Construction Detail D1.7.36 Miscellaneous Penetrations (Guardrails).