Template:Part 10 (Waterproofing Roofs - Single-ply)

1 General

1.1 Definitions

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

Low Door

means a door with a rough opening less than 200 mm (8”) above the finished roof surface, but no less than 100 mm (4”) above the roof membrane.

Standard Door

means a door located at least 200 mm (8”) above the finished roof surface.

Tall Parapet

means a parapet taller than 600 mm (24”).

1.2 Design

1.2.1 RoofStar 15-Year Guarantee

1. Refer to 1.3.1 RoofStar 15-Year Guarantee for general requirements, to qualify the Project for a RoofStar 15-year Guarantee.

1.2.2 All Projects

1. The Design Authority is responsible to specify the sequencing of construction so that intersecting systems are positively connected. See 10.3.2 Sequencing.
2. All membranes must be fully adhered to vertical substrates, and when the membrane terminates on the vertical face of the wall or parapet, it must be mechanically secured at the membrane termination.
3. When a roof Waterproofing System transitions to
   1. a high wall, additional mechanical securement may be required by the manufacturer.
   2. a sloped or vertical plane, the transition may be made with a continuous membrane from the field, or with a separate membrane flashing. In either case, the membrane must be
      1. fully adhered.
      2. mechanically secured at the upper termination.
      3. lapped onto the field membrane in keeping with the membrane manufacturer’s published specifications, or as otherwise stated in these Standards.
4. Except where low parapets, metal fascia edge flashings and low door sills or window details are incorporated in the design (see also 10.3.7 Door Openings), 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, membrane flashing must be carried vertically past the top surface of the covering (the Finished Waterproofing System) at least 200 mm (8”).
5. Regardless of parapet height, membrane flashing must be carried up the inside face of the parapet walls no less than 200 mm (8”) above the Finished Waterproofing System.
6. Tall parapets should be designed with consideration given to ventilation.
7. Parapets are not required at the edge of a Conventionally Insulated System that does not support overburdens, but when they are specified and constructed they must be no less than 125 mm (5") in height, measured from the finished roof surface to the inside top edge of the parapet, in order to facilitate proper metal cap flashing securement. See also 13.3.4 Cap, Counter and Base Flashings.
8. When a roof is designed to support Overburden or is held in place with ballast, the roof must be designed to retain the Overburden or ballast against wind scouring, but in any event must be designed with parapets at least 200 mm (8”) in height when measured from the top surface of the overburden or ballast. See also Part 3 SECURING the ROOF ASSEMBLY.
9. Mechanical fasteners used to secure a metal flashing or wall finish must be installed at least 89 mm (3 ½”) above the finished roof surface.
10. When a wall or parapet is faced with multi-wythe masonry or composite panels, and the membrane flashing must be installed over the face of the wall or parapet, the through-wall flashing that separates wythes or courses of panels must be
    1. supplied and installed by others.
    2. situated at the next course above the terminated edge of the membrane flashing and any metal roof flashings. Refer to current seismic codes for suitability.

    In the alternative to the above, the entire inside face of a parapet wall must be completely flashed or cladded.

11. When a metal edge termination detail is used, the edge must be fully blocked to support the metal and membrane edges.
12. Cant edges are not required or recommended, since single-ply membranes are manufactured to transition from horizontal to vertical planes without the assistance of a cant. Cant edges on existing roofs may be left in place, at the discretion of the Design Authority.
13. When a Waterproofing System transitions
    1. down a slope onto a lower Water-shedding System, the Waterproofing System membrane must positively lap the Water-shedding System by no less than 50 mm (2").
    2. up a slope and beneath a Water-shedding System,
       1. the Waterproofing System membrane must extend up the Water-shedding slope at least
          1. 150 mm (6”), or
          2. 300 mm (12”) in regions with typical heavy snow.
       2. fasteners for the Water-shedding System must be at least 89 mm (3 ½”) above the finished surface of the Waterproofing System(when measured vertically).
       3. the Water-shedding System materials must overlap the Waterproofing System by at least 150 mm (6”).
    3. with a wall, wall membranes and finishes must positively lap membrane flashing by at least 75 mm (3").
14. Where a roof allows water to freely drain off the edge, a cricket or diverter should be installed at the roof edge where the roof adjoins a wall, to prevent water intrusion behind wall finishes.

2 Materials

2.1 Membranes

1. Membranes used to flash (strip) walls, parapets or other edges may be the same as the membrane used on the field, but in any event must conform to the membrane requirements found in 9.2.1 Composition, Thickness and Selection.
2. When a Waterproofing System transitions with a Water-shedding System, the intersecting materials must be compatible with each other.
3. When cant edges are specified, they must be fabricated from wood.

2.2 Fasteners

1. Fasteners used to secure the upper termination of membranes must be the fasteners specified by the membrane manufacturer or, when a fastener is not specified, a #12 screw-type fastener or impact-driven fastener compatible with all secured materials.

2.3 Metal Flashings

1. Linear Metal Flashings incorporated into roof perimeters and walls must conform to the materials and fabrication standards found in 13.2 Materials.

3 Application

3.1 General

3.1.1 RoofStar 15-Year Guarantee

1. Refer to 1.3.1 RoofStar 15-Year Guarantee for general requirements, to qualify the Project for a RoofStar 15-year Guarantee.
2. EPDM membrane system Projects only: all outside corners must be double-wrapped using semi-cured membrane, installed according to the membrane manufacturer’s published details and written requirements.

3.1.2 All Projects

1. All installed membranes must be protected from splashed or dripped primer. This standard also applies to work by other trades, who may use primers for self-adhering membranes typically installed on walls or around doors, windows or other wall penetrations.
2. Membrane flashing plies must be installed according to the manufacturer's published instructions, but in any event must be
   1. installed from the low point of the roof (for positive laps toward the drain).
   2. wrapped over the top of the parapet or roof edge and down the outside face by at least 50 mm (2”).
   3. extend
      1. onto the field of the roof, as required by the membrane manufacturer, when separate membrane flashing plies are used.
      2. up a vertical surface at least 200 mm (8") above the roof field membrane or roof covering, 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, membrane flashing must be carried vertically past the top surface of the covering (the Finished Waterproofing System) at least 200 mm (8”).
   4. installed without fish-mouths or wrinkles, hand-rolled with a membrane manufacturer’s accepted roller and fully bonded to an acceptable, prepared substrate.
   5. reinforced at all inside and outside corners with membrane corner details or seam transition covers
      1. wherever the membrane flashing changes planes (vertical to horizontal, for example).
      2. installed in accordance with the manufacturer’s published instructions.
   6. mechanically secured at the termination of the membrane flashing and protected with an acceptable Linear Metal Flashing.
   7. finished and sealed before the end of the working day.
   8. correctly lapped with any wall membranes or finishes by at least
      1. 75 mm (3”) when installed underneath wall materials.
      2. 50 mm (2”) when installed over wall materials.
3. All membranes or membrane flashing terminating on any vertical surface must be secured to the vertical substrate by the Contractor. Exposed membrane edges must also be protected from water intrusion. This must be accomplished using one of the following options, ranked according to the maintenance they require (low to high):
   1. Adhere the roof membrane to the wall surface, and
      1. protect the exposed membrane edge with overlapping wall membranes and exterior sheathing (Figure 10.3.1a).
      2. cover the exposed membrane edge with a secondary, fleece-reinforced 2-component liquid membrane flashing (use only with a RoofStar-accepted liquid flashing materials specifically acceptable to the membrane manufacturer) (Figure 10.3.1b).
   2. Mechanically secure the membrane to the wall with a proprietary termination bar fastened no more than 300 mm (12”) O.C.; caulk the upper edge of the termination bar and cover the bar with a cut reglet flashing sealed inside the reglet cut with an acceptable sealant (see 13.2.4 Sealants) (Figure 10.3.1c).
   3. Mechanically secure the membrane to the wall with a proprietary termination bar fastened no more than 300 mm (12”) O.C.; caulk the upper edge of the termination bar and cover the bar with a secondary metal surface reglet flashing that is separately attached to the wall (no more than 300 mm (12”) O.C.) and sealed along the upper edge with an acceptable sealant (see 13.2.4 Sealants) (Figure 10.3.1d).
   4. Mechanically secure the membrane to the wall; surface-mount a reglet flashing above the terminated membrane and seal the metal flashing along the upper edge with an acceptable sealant; install a second surface-mounted reglet flashing and seal it along the upper edge with an acceptable sealant (see 13.2.4 Sealants) (Figure 10.3.1e). See also 13.3.5 Cap, Counter and Base Flashings for Linear Metal Flashing requirements.
4. When the roof membrane is mechanically secured with a termination bar or a metal flashing, fasteners must be spaced no more than 300 mm (12”) O.C. When closer spacing is required by the membrane manufacturer, the wall must be constructed or modified to facilitate solid fastener securement.
5. When a second Linear Metal Flashing is installed to protect a termination bar or flashing used to secure the membrane, it may be fastened no more than 600 mm (24”) O.C. provided the metal flashing maintains continuous contact with the substrate. See also 13.3.1 General (Application).
6. Membranes that intersect with Water-shedding Systems must be installed in keeping with 10.3.5.3.
7. Membranes on parapets that intersect with a higher wall must be sealed with a membrane saddle formed to protect the inside and outside corners.

3.2 Sequencing

1. Projects must follow proper sequencing. This means that materials must be installed so that they interface with other materials, systems or assemblies, including those installed by other trades, in “shingle fashion” by positively overlapping them below or above. Occasionally, the coordination with other trades requires some adaptation to this standard. When that is the case, any variance to proper detail sequencing must be approved by the Design Authority in writing.

3.4 Membranes

3.4.2 Self-adhered

1. Self-adhered membranes must be installed on a clean, uncontaminated surface. Dirty or contaminated surfaces must be covered with
   1. plywood sheathing with a minimum nominal thickness of 9.5 mm (3/8").
   2. a wall overlay.

3.4.3 Adhesive and Hot Asphalt-adhered Membranes

1. Adhered membranes must be installed on a clean, uncontaminated surface. Dirty or contaminated surfaces must be covered with
   1. plywood sheathing with a minimum nominal thickness of 9.5 mm (3/8").
   2. a wall overlay.
2. Hot-asphalt adhered membranes must be installed according to the membrane manufacturers’ installation specifications.

3.5 Perimeters and Walls

3.5.2 Metal Edge Terminations

Membrane roof Waterproofing Systems may be terminated at the roof edge, flush with the roof surface, using a linear metal edge flashing. Metal edge flashings must be installed to the following standards:

1. Conventionally Insulated Systems terminating on the horizontal plane with a metal edge flashing must abut blocking at the roof edge.
2. Metal edge flashings must be
   1. installed over a separation layer of membrane flashing that extends onto the roof field at least 50 mm (2”) and down the outside face of the roof edge at least 50 mm (2”).
   2. fastened to the roof surface with mechanical fasteners
      1. placed at least 50 mm (2”) away from the outside edge.
      2. spaced 200 mm (8”) O.C. in offsetting rows.
   3. joined to each other with lap joints measuring at least 100 mm (4”), and sealed with caulking (see the requirements in 13.3.4 Seams).
   4. sealed to the membrane, which must extend
      1. at least 100 mm (4") onto the metal flashing, and at least 50 mm (2”) past the fasteners.
      2. at least 100 mm (4”) onto the field membrane, when utilizing a cover strip.
3. When a metal diverter flashing is required, it must be fabricated like a metal edge flashing, and must be secured and sealed to the primary membrane with membrane flashing (stripping).

3.5.4 Transitions with Water-shedding Systems

1. Where two roof systems intersect, materials must be compatible with each other, or must be separated from contact by an intermediate separation layer.
2. When a Waterproofing System transitions
   1. down a slope onto a lower Water-shedding System, the waterproofing membrane must lap over the Water-shedding System by no less than 50 mm (2").
   2. up a slope and beneath a Water-shedding System,
      1. the field membrane or membrane flashing must extend up the Water-shedding System slope at least
         1. 200 mm (8”), plus 75 mm (3”) for the overlap by the Water-shedding System, when measured vertically from the water plane, or 150 mm (6”) when measured vertically from the maximum water level.
         2. 300 mm (12”) plus 75 mm (3”) for the overlap by the Water-shedding System, when measured vertically from the water plane or maximum water level, in regions with typical heavy snow.
      2. the termination of the membrane on the slope must be mechanically secured, separately from the Water-shedding System.
      3. fasteners for the Water-shedding System must be at least 200 mm (8”) above the Finished Waterproofing System (when measured vertically from the water plane), or 300 mm (12”) for regions with heavy snow.
      4. the Water-shedding System materials must overlap the Waterproofing System by at least 150 mm (6”).
   3. with a wall, wall membranes and finishes must positively lap membrane flashing by at least 75 mm (3").

3.6 Expansion and Control Joints

See 2.4 Expansion Joints and 2.5 Control Joints above. Membrane application must conform to the general requirements outlined in 10.1 General.

1. Expansion joints constructed as a raised divider must have a sloped top surface and must extend in height above the Finished Waterproofing System no less than 200 mm (8"). The minimum height of the expansion joint may be reduced to 100 mm (4") if the primary roof membrane flashing is fully supported and sealed over the top.
2. Proprietary elastomeric expansion joint systems, manufactured with an EPDM-based core and flanges that can be fully bonded to the primary membrane, are acceptable for use in Waterproofing Systems when the systems are located a minimum of 200mm (8") above the Finished Waterproofing System and are completely sheathed (covered) with sloped Linear Metal Flashing. Such joints must be
   1. accepted for use in the RoofStar Guarantee Program.
   2. compatible with the roof membrane and acceptable to the membrane manufacturer.
   3. designed and manufactured to accommodate building movements of at least 500% elongation at -40°C (-40°F) across its length and at all vulcanized points.
   4. factory-fabricated by means of vulcanization.
   5. manufactured as one piece, complete with all joints, details and connections.
   6. bonded with the primary membrane in a manner acceptable to the manufacturers of both the expansion joint and the membrane to which it will be bonded.
3. Field splicing of proprietary elastomeric expansion joints is permitted only when made with a machine acceptable to the expansion joint manufacturer. All other field splices are not permitted.

3.7 Door Openings

1. Standard door openings must be flashed with membrane, reinforced with gussets at the sill corners, carried vertically on all surfaces of the door sill opening at least 100 mm (4”)
2. The RGC recommends against low door openings because of their propensity to leak. Nevertheless, when a low door opening is specified to comply with building codes, it must be waterproofed in keeping with the following standards:
   1. The opening at the curb must be waterproofed before the door frame and sill is installed, by one of the following accepted methods:
      1. Sheet membrane flashing
         1. reinforced with gussets at the sill corners.
         2. carried vertically on all surfaces of the door sill opening at least 100 mm (4”).
         3. terminated on a mechanically attached water-stop flashing sized to underneath the door sill and sealed to the opening with membrane flashing.
      2. A metal water stop flashing, fabricated with folded, welded or soldered corners and mechanically attached to inside of door sill opening. The pan must be sealed to the door curb and opening with membrane flashing.
      3. Reinforced liquid membrane flashing applied in keeping with the requirements for sheet membrane flashings above.
   2. The roof must be sloped away from the door opening.
   3. Overflow drains must be
      1. installed on the same roof area and located at least 25 mm (1") below the door sill.
      2. capable of flow rates equivalent to or greater than those of the primary roof drains for the roof areas adjacent to the door opening (see also 11.3.2.5 Scuppers and Overflows).
   4. When the building interior transitions to a patio or occupied roof surface through a flush door opening, the walking surface of the patio or roof must protect the roof membrane from damage and provide a drainage space below the walking surface measuring at least 12.7 mm (1/2”). Alternatively, pea gravel installed on a drainage board may be used.
   5. Overhangs above the door are recommended wherever practical, to minimize water intrusion that occurs from wind-driven rain or from snow accumulation.

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