Grade-level Waterproofing Standard

This section contains the Standards, Guiding Principles, Recommendations and reference materials necessary for the design and installation of a roof qualifying for a RoofStar Guarantee.

How to use the Guarantee Standards section:How to use the Guarantee Standards section:

All relevant Standards for the selection and application of materials necessary to qualify for a RoofStar Guarantee are found in this section. Readers are advised to review relevant materials that can be accessed through the links available in the body of text or embedded in section titles; these are shown in blue font. Subsection titles shown in blue indicate links to more relevant material that the reader is advised to consult.

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1 ABOUT WATERPROOFING

1.1 Waterproofing versus Dampproofing

The definition of waterproofing is the treatment of surfaces or structures in order to prevent the passage of water under hydrostatic pressure. In contrast dampproofing is defined as the treatment of surfaces or structures to resist the passage of water in the absence of hydrostatic pressure. The hydrostatic pressure exerted by water lying against a barrier increases steadily in pressure as the depth of water increases. Water exerts a pressure of 1000kg per meter squared per meter of depth or 62.2 pounds per square foot per foot of depth. Standing water is often present on plaza decks which are typically horizontal low-sloped suspended structural decks over occupied spaces, subsequently this makes waterproofing and protected roofing systems, not dampproofing, the only reliable options to prevent the passage of water into structures.

1.2 Comparisons: Waterproofing, Conventional & Protected Membrane Roof Systems

The differences between waterproofing and low slope protected roofing membrane systems can be very subtle with many manufacturers' membranes often being interchangeable for both roofing as well as waterproofing applications on plaza decks. The two main features differentiating protected membrane roofing systems from waterproofing systems are the membrane flashing application techniques used at construction details and the type of wearing and or protection course used over the membrane assemblies. In contrast conventional roof systems are typically installed over insulations with the primary roof membrane exposed to weather or protected by light aggregates or coatings. (For additional technical information on Protected Membrane Roofing Systems refer to Section 3.13 of this manual, RPM).

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2 GENERAL REQUIREMENTS

The information provided in this section of the RCABC Roofing Practices Manual (RPM) contains standards to follow for RoofStar guarantee coverage. It also includes technical information and recommendations to assist designers and applicators with waterproofing membrane applications on plazas, promenades and terraces. The formulation of the content of this section of the RPM is based upon the advice of, and information from, architects, manufacturers as well as the experiences of RCABC member professional roofing and waterproofing contractors.

RoofStar Guarantee Standards for Waterproofing are applicable to Plazas / Promenades and Terraces only. Vehicle parking structures, below grade walls, foundations, and repairs or renovations to existing waterproofing systems do not qualify for RGC guarantee coverage. In addition, all waterproofing system components, including but not limited to membrane protection materials, drainage layers, overburdens including wearing course materials, must comply with and be installed to RGC Guarantee Standards E, in order to qualify for RGC guarantee coverage.

2.1 Deck Slopes

A minimum slope of 1:50 (l/4" in 12") is strongly recommended for waterproofing systems, but positive slope to drain is an absolute requirement. To take advantage of future loading deflections drains should be located at mid-spans between deck supporting columns, whenever practical, and especially when deck slopes are less than 1:50 (1/4” in 12”). Positive slope to drain is attained when no standing water remains on the deck within a reasonable amount of time after rainfall stops during days with conditions that permit evaporation. Refer to Essential Elements: Roof Decks for additional information on decks and the definition of slope to drain.

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3 DECKS

3.1 Deck Types

3.1.1 Wood

Wood decks are not acceptable substrates for waterproofing systems that are covered under the RGC Guarantee Program. (Refer to Section 3 for information on wood decks for Roofs.)

3.1.2 Concrete

3.1.2.1 General

Cast in place, monolithic structural concrete slabs and precast concrete panels with concrete topping (average 50mm thick) as well as concrete toppings over steel decks make the best substrate and are the most common deck types used for plaza, promenade and terrace waterproofing substrates. Light weight insulating concrete and shotcrete formed concrete decks are not good substrates for waterproofing and therefore are not acceptable decks for waterproofing systems covered under the RoofStar Guarantee Program.

RGC strongly recommends a minimum of 2% (1/4" to ft.) slope to drain for all substrates that receive waterproofing but positive slope to drain is an absolute requirement. It is recommended that drains be located at mid-spans between deck supporting columns whenever deck slopes are less than 1:50 (1/4" in 12") in order to take advantage of expected loading deflections. Positive slope to drain is attained when no standing water remains on the deck 48 hours after a rainfall stops during days with temperatures that permit evaporation. Standard weight concrete (150 pcf) can experience deflection resulting from long-term creep due to loading and to assure permanent retention of a minimum of 1% (1/8" to ft.) an initial slope of at least 2% is strongly recommended for concrete decks.

Creep in structural concrete, both reinforced and pre-stressed, due to increasing constant prolonged loading can result in deck deflections equal to three times instantaneous elastic deflection. Therefore, plaza decks with heavy overburdens (loading) require special attention from the structural engineer during the design process to ensure that load carrying capacity of the deck is adequate. The structural design of plazas must also contend with possible intermittent live loads that may exceed 50% of the total design load. The service weight of emergency vehicles such as fire trucks can concentrate excessive live loads on plaza decks that are often designed to provide access for emergency vehicles.

Concrete waterproofing decks include decks that are cast-in-place or pre-cast, and structural or non-structural in nature. The finished surface of the deck should be smooth, level, and free of moisture or frost. With cast-in-place decks, special care must be taken to ensure that the deck is cured for 28 days and that the surface is dry. For compliance with National Building Code of Canada provisions for the design and construction of buildings their structural members made of plain, reinforced and pre-stressed concrete shall conform to CSA A23.3 "Design of Concrete Structures".

3.1.2.2 Installation

1. Concrete decks, walls, curbs and equipment pad surfaces must be clean (free from dirt, loose particles, paint, silicone, oil, grease, curing compounds or agents, adhesion inhibiting curing compounds and release agents as well as other contaminants). Concrete decks also must be dry and smooth (free from sharp projections) prior to commencement of waterproofing installations.
2. Pitted or honey-combed surfaces must be repaired before the membrane application and is the responsibility of others, not the waterproofing contractor, unless specified otherwise. Holes or voids in the concrete substrates must be re-pointed with a non-shrinking concrete patching compound.
3. Concrete decks, walls, curbs and equipment pads are not to receive adhered waterproofing for a minimum of 28 days after pouring unless expressly instructed in writing by the Project Structural Engineer. Decks formed with shot-crete and lightweight insulating concrete are not acceptable substrates for waterproofing under the RGC Guarantee Program.
4. The moisture content levels of concrete surfaces, decks, walls, curbs and equipment pad surfaces, must strictly comply with the membrane manufacturer’s published moisture level application limitations.
5. All concrete surfaces to receive adhered waterproofing shall be structurally sound, water cured, have a light hair broom finish or be prepared by mechanical means and shall be primed, when applicable, with a membrane manufacturer’s approved primer. Proper water curing techniques are strongly recommended and include continual or frequent applications of water by ponding or immersion, spraying or fogging. Concrete decks cured with compounds or sealants may not have acceptable surfaces to receive adhered waterproofing membranes. When concrete curing compounds are used on waterproofing decks removal of the compounds by mechanical means, may be necessary prior to installation of membranes, and such removal is the responsibly of others not the waterproofing contractor.
6. Curbs, blocking, and nailing strips should be installed where required prior to the waterproofing contractor's acceptance of the deck.
7. Pre-cast panels, post-stressed beams, or “T” and cavity decks shall have a minimum 50mm (2”) concrete topping applied over the deck prior to the application of the waterproofing membranes. Where a difference exists in the levels of adjacent surfaces, the general contractor or others shall install approved non-shrink grout or ground to match level of adjacent surfaces. Grouting or grinding shall be feathered on the lower surface a minimum distance of twelve times the amount of the vertical differential.
8. Cold joints between concrete pours, at transitions between horizontal decks and vertical walls below grade, shall be sealed and covered with waterproofing membrane flashing. Membrane flashing shall cover all deck wall transitions by a minimum of 200mm (8”) and both deck and wall waterproofing or damp proofing materials must be compatible with one another. Or alternatively, whenever materials at deck and below grade wall transitions are not compatible with one another sealants and mechanically attached termination bars are acceptable, to create a watertight lap a minimum 200mm (8") in width.

3.1.2.3 Substrate Moisture Emissions

Concrete decks can retain water for extended periods and when exposed to rain the drying time will be extended beyond 28 days. Adhered waterproofing systems require concrete deck moisture levels that are low enough to ensure an adequate bond between the deck and the waterproofing materials. Many waterproofing materials application specifications require that moisture levels emitted from concrete decks not exceed three (3) pounds per thousand square feet.

Testing moisture levels that are emitted from concrete decks prior to material applications is an RGC Guarantee Standard and an essential step in minimizing the impact that the presence of water may have on successful waterproofing application. Moisture meters are used to determine the moisture content of concrete decks and must be performed daily by the applicator prior to waterproofing membrane installations. Capacitance testing meters measure the relative moisture content of the surface of concrete decks in order to determine the suitability of the surface (to 25mm -1" in depth) for the application of adhered materials.

3.1.3 Steel

3.1.3.1 General

Steel roof decks are most often constructed of light gauge (usually 22, 20, or 18 gauge) cold-rolled steel sections (panels) that are galvanized. In cross-section the panels are ribbed, with the ribs usually spaced at 150 mm (6") on centre. The ribs provide the strength and rigidity of the panels. Steel decks are generally supported by open-web steel joist framing and are welded or mechanically fastened to the framework. Steel decks panels must be properly aligned, squarely intersect walls, and provide a smooth level surface for waterproofing.

For compliance with National Building Code of Canada provisions for the design and construction of buildings their structural members made of cold-formed steel shall conform to Can / CSA -S136-01 (including supplement CAN/CSA -S136S1-04).

3.1.3.2 Installation

Poured concrete, gypsum or cement fibre board deck overlays are required over steel decks as acceptable substrates for all adhered waterproofing membrane systems.

1. Steel Decks with Concrete Overlays

Steel decks that receive poured concrete overlays shall have vented pans to prevent entrapment of moisture. For preparation of concrete surfaces for membrane applications refer to 2.2.4 above.

2. Gypsum Boards on Steel Decks

Two layers of gypsum board shall be installed over steel decks as an acceptable substrate for adhered waterproofing membranes when cast in place concrete topping is not present. The first layer of gypsum or cement board shall be either be fully mechanically fastened to the deck or adhered to the deck with manufacturer's approved compatible polyurethane adhesive. The second board layer must be adhered with a compatible manufacturer's approved polyurethane adhesive.

All edges of the gypsum & cement boards must be fully or intermittently supported by the deck. Staggered (offset) end and side joints 300 mm (12") from adjacent board rows. All board joints that will receive liquid applied membrane systems must be taped with waterproofing manufacturer's approved joint tape.

Each layer shall be a minimum thickness of 12.7 mm (1/2") and must be manufactured with fibreglass facers and silicone treated gypsum cores, conforming to ULC S-102 & ULC S-107. Gypsum board edges shall to be fully or intermittently supported by the deck and have joints staggered (offset) 300 mm (12") from adjacent boards, rows or layers.

All board joints that will receive liquid applied membrane systems must be taped with waterproofing manufacturer's approved joint tape. In all other circumstances, and when required by membrane manufacturer's application specifications, tape all board joints that will receive membrane using the waterproofing manufacturer's approved joint tape.

For board surface preparations (e.g. primer) follow membrane manufacturer's application specifications.

3. Cement Fibre Boards on Steel Decks

Two layers of fibre-mat reinforced cement board shall be installed over steel decks as an acceptable substrate for waterproofing membrane applications and each layer must be a minimum thickness of 9.5 mm (3/8") as well as conform to ASTM C1325-04 Non-Asbestos Fibre-Mat Reinforced Cement Substrate Sheets.. Cement fibre-mat board edges shall to be fully or intermittently supported by the deck and have joints staggered (offset) 300 mm (12") from adjacent boards, rows as well as layers. When required by membrane manufacturer’s application specifications tape all board joints that will receive membrane with waterproofing manufacturer’s approved joint tape. For board surface preparations (e.g. primer) follow membrane manufacturer’s application specifications.

3.1.3.3 Mechanical Fastening: Gypsum Board & Cement Board Attachment on Steel Decks

When gypsum or cement boards are mechanically fastened on steel decks, as substrate overlay boards for waterproofing membranes, the first layer of gypsum or cement board shall be either fully mechanically fastened to the deck or be adhered with membrane manufacturer’s approved polyurethane adhesive. The second layer must be adhered with membrane manufacturer’s approved polyurethane adhesive. Mechanical fixation through both deck overlay board layers is not permitted.

Maximum steel deck flute width and minimum fastener requirements for gypsum and cement board used for deck overlay applications are as follows:

Minimum fasteners using Screws and/or Plastic or Steel Stress Plates

Thickness	Deck Flute Width	Board Size	Screws & Metal Stress Plates	Bulgle-head Drywall Screws
9.5 mm (3/8”)	up to 125 mm (5")	1200 mm x 2400 mm (4' x 8’)	12	32
12.7 mm (½")	up to 125 mm (5")	1200 mm x 2400 mm (4' x 8’)	12	32
15.9 mm (5/8")	up to 200mm (8")	1200 mm x 2400 mm (4’ x 8’)	12	32

3.2 Expansion Joints

3.2.1 General

Expansion joints are used on waterproofing decks to intentionally provide periodic breaks or gaps to accommodate movement for the expansion and contraction of the buildings as well as thier components. Typically movement is limited to a maximum of 25mm (1"). Expansion joints can be found at changes in deck direction, re-entrant building corners, and changes in deck type as well as on large decks exceeding 61meters (200') additions and buildings with extreme movement (freezers) or when isolation from vibrations is required.

3.2.2 Elastomeric Expansion Joints

Flat profile expansion joints (joints at the water plane/deck level) must be elastomeric expansion waterproofing joints with all details and connections factory fabricated by means of vulcanization. Field splicing of two pieces of flat profile expansion joints by other than the expansion joint manufacturer, typically by use of adhesives, caulking, taping or hot air welding, is not permitted under the RoofStar Guarantee Program. Flat profile expansion joints must be designed to accommodate expected building movements and be capable of a minimum of 500% elongation at - 40°C (- 40°F) across its length and at all vulcanized points.

Elastomeric expansion joints must be compatible with the waterproofing membrane and acceptable for use by the membrane manufacturer.

3.2.3 Other Expansion Joints

Roof expansion joint systems that do not meet the requirements set out in 3.2.2 (above) are acceptable under the RoofStar Guarantee Program when the joints are located a minimum of 100mm (4") above the finished roof surface and are completely sheathed (covered) with membrane flashing and sloped metal flashing (for cross-reference, see D1.7.16 Roof-Wall Transitions (Expansion Joint)).

3.3 Tying Into Existing Waterproofing

Where a new waterproofing system is tied-in to an existing system, the waterproofing materials must be compatible with one another, provide a positive water cut-off to the deck and shall have an RGC accepted membrane moisture monitoring sensor grid system installed between the new and existing waterproofing systems.

RGC accepted membrane moisture monitoring systems are listed in the Accepted Materials section of this Manual.

4 MATERIALS

Waterproofing materials and systems that are accepted for use in the RoofStar Guarantee Program include SBS Modified Bituminous, Polyvinyl Chloride (PVC) and Butyl (Isobutylene & Isoprene) pre-manufactured membranes, together with Hot Fluid-Applied, Reinforced Rubberized Asphalt Systems. Waterproofing materials and systems covered by the RoofStar Guarantee Program are listed under Accepted Materials section of this Manual. In order to qualify for full coverage under the RoofStar Guarantee Program the waterproofing system as well as installation details must comply with the RGC Guarantee Standards set out in this Manual, with with the Membrane Manufacturer's specifications for plaza, promenade or terrace decks applications.

5 SUBSTRATES: Walls and Wall Preparation

5.1 Application

5.1.1 Wall Sheathing

Gypsum board is not considered an adequate substrate to receive waterproofing on vertical surfaces.

On steel framed walls fibre-mat reinforced cement board with a minimum thickness of 9.5 mm (3/8") that conforms to ASTM C1325-04 (Non-Asbestos Fibre-Mat Reinforced Cement Substrate Sheets) is an acceptable substrate to receive waterproofing. Fibre-mat reinforced cement board is to be supplied by others unless specified otherwise, must be installed by the waterproofing contractor, and covered with membrane the same work day.

5.1.2 Concrete Wall Preparation

All concrete or masonry parapets and walls must provide a smooth, clean, dry surface for membrane adhesion. Alternatively walls that do not provide a smooth, clean, dry surface for membrane adhesion may be sheathed with a minimum 15.9 mm (5/8") treated plywood or 9.5 mm (3/8") reinforced cement board that conforms to ASTM C1325-04. Boards must be mechanically attached or adhered to the wall with polyurethane adhesive. When waterproofing is applied directly to masonry parapets or walls follow RGC guarantee standards and manufacturer's printed instructions.

5.1.3 Walls at Decks Not Supported by the Wall

A parapet wall is required at adjoining walls were the deck is not supported by the wall (expansion joint) and shall be sheathed with minimum 15.9 mm (5/8") plywood or 9.5 mm (3/8") reinforced cement board that conforms to ASTM C1325-04. Wall sheathing shall be fastened to preservative treated blocking or to steel stud framing that is attached solidly to the deck and not the wall. Compressible insulation is to be installed between the sheathing and the wall and an accepted expansion joint membrane as well as metal counter flashing shall be installed.

5.1.4 Planter Walls

Non-structural planter walls that are located above protection and drainage board layers, without penetrating waterproofing membranes, are strongly recommended whenever practical. When planter walls have structural reinforcements that penetrate membranes only the use of pre-curbs or start-up curbs that are a minimum height of 100mm (4") above the deck are acceptable for coverage under the RGC Guarantee Program.

For further reference, see Section 12 below, LANDSCAPING, PLANTERS & OTHER VEGETATED OVERBURDENS, together with Construction Detail drawing F1.7.6 - Walls (Planter Pre-Curb Wall).

6 MEMBRANES

6.1 General

RGC specifically accepted waterproofing membrane systems listed in the Accepted Materials of this Manual include the following:

• Two Ply SBS Modified Bituminous Membranes
• Butyl Elastomeric Single Ply Membranes
• Poly Vinyl Chloride (PVC) Plastomeric Single Ply Membranes
• Hot Fluid - Applied, Rubberized Asphalt Systems.

Only waterproofing membrane systems that are fully adhered and have an accepted protection layer installed above the membrane (protected) qualifies for coverage under the RoofStar Guarantee Program.

All waterproofing system accessory components must be supplied or be accepted for use by the membrane manufacturer. Refer to Section 9 for individual manufacturer accessory components and material listings.

All materials must be protected from weather by properly stacking above ground or deck surfaces and keep in factory packaging or other adequate covering until applied.

6.2 Material Selection

6.2.1 SBS Modified Bitumen Membranes

6.2.1.1 General

SBS (Styrene Butadiene Styrene) Modified Bituminous sheet waterproofing is prefabricated elastomeric membranes that are reinforced with mats consisting of polyester, fibreglass or a combination of both reinforcement types. SBS modified bituminous membranes are available in varied thicknesses with specific physical properties to satisfy the demands of particual waterproofing conditions as well as surface finishes that facilitate various application methods.

6.2.1.2 Composition

Bituminous and modified bituminous flexible membrane systems are composite sheet membranes which are thermoplastic in nature but display variable elastomeric properties when modified. These sheets generally consist of bitumen (oxidized or modified), reinforcement, and surfacing materials. The performance of these membranes may be compromised by subtle, seemingly inconsequential changes in composition.

The formulation of the bitumen is critical, particularly when its physical properties are modified by the addition of polymers. Bitumen is most commonly modified with styrene butadiene styrene (SBS). The manufacturer must ensure that a suitable degree of compatibility exists between the bitumen and the polymer and that a thorough mix has been obtained. The careful selection and combination of bitumen and polymer (the type of modifier, the percentage of polymer used, etc.) determines the physical properties and long term performance of the modified bituminous "binder". The binder provides the membrane with its waterproofing capability and may impart the following properties:

• low temperature flexibility
• elasticity
• high temperature resistance to flow
• resistance to aging

The bitumen utilized for oxidized bituminous membranes has been "blown", similar to roofing asphalt. This produces a higher softening point and, therefore, a more useful temperature range.

The physical properties of the binder are further enhanced by the imposition by saturation or coating onto a carrier or reinforcing mat, most commonly a textile such as:

• non-woven spun-bonded polyester
• woven polyester scrim
• fibreglass mats
• woven fibreglass cloth
• combinations of the above.

6.2.1.3 Requirements

.1 All SBS Modified Bituminous membrane waterproofing systems shall consist of two plies of membrane. The top ply or cap sheet shall have a minimum thickness of 2.9 mm and a minimum reinforcement weight of 180g/meter squared polyester or equal strength combination reinforcement. In addition, both base plies and cap sheets in combination shall have a minimum thickness of 6.0mm or greater.

.2 Both the base sheet and cap sheet must be installed in a parallel direction (not at 90° to each other). Manufacturer's published instructions for membrane overlaps, sheet installation configurations, corner gussets (reinforcement) and membrane flashing applications shall be strictly followed. Membrane reinforcement gussets shall be installed at all inside and outside corner transitions prior to installation of membrane flashing (stripping).

.3 Only fully adhered SBS base and cap sheets that are either torch applied or are adhered in hot fluid applied rubberized asphalt qualify for coverage under the RGC waterproofing guarantee program. NOTE: Direct torch applications to wood surfaces are not permitted.

.4 Membrane end lap corners must be cut on a bias (clipped or trimmed on an angle) prior to forming laps on all torch applied modified bituminous membranes and granules are to be embedded on cap sheets prior to forming laps or seams.

6.2.2 Thermoset Membranes

6.2.2.1 General

Thermoset is defined as a material that solidifies or "sets" irreversibly when heated (vulcanized). This property is usually associated with cross-linking of the molecules induced by heat or radiation. Once the material is cured, it can only be bonded to itself by adhesives; new molecular linkages cannot form. Some thermosets are not cured during manufacture (ie. Butyl flashings) and are intended to cure over time after they have been installed. This allows the material to cure into the specific shape required for waterproofing application details.

6.2.2.2 Composition

The generic membrane types defined as cured thermosets in the RoofStar Guarantee Program for Waterproofing currently include Butyl Membranes (Isobutylene and Isoprene):

Butyl (Isobutylene - Isoprene) membrane is a thermoset vulcanized elastomer synthetic rubber membrane formulated from isobutylene and Isoprene. Although most commonly available as a cured sheet, butyl can be formulated as an uncured membrane for specific purposes (i.e., flashings).

Butyl membrane waterproofing systems are single-ply membranes in 1.5 mm (0.060") and greater thicknesses and are usually black in colour. The membrane is applied fully-adhered and seams are joined with contact splicing cement or seaming tape (or a combination of both), and are caulked (see manufacturer's requirements).

Butyl membranes should conform to CGSB 37-GP-52M 1984, "Roofing and Waterproofing Membrane, Sheet Applied, Elastomeric" which lists two Classes of Type 2 reinforced membranes (classed according to their end-use), according to manufacture:

• Class A - exposed
• Class B - non-exposed

This standard covers requirements such as "thickness, tensile strength, breaking strength, lap joint strength, elongation, tensile set, low temperature flexibility, water absorption, dimensional stability after water absorption, heat aging, ozone resistance, resistance to accelerated weathering, dynamic impact test, tear resistance, and tearing strength."

6.2.2.3 Requirements

.1 Butyl single-ply thermoset waterproofing membranes used for waterproofing systems shall be fully adhered to RGC accepted substrates and shall be a minimum thickness of 1.5mm (0.060”).

.2 Only proprietary adhesives that are specifically accepted by the membrane manufacturer may be used to install Butyl membrane waterproofing systems.

.3 Perimeter fixation for membrane securement (mechanical, adhesive, or adhesive tape), installed to manufacturer’s published specifications, is required for all Butyl waterproofing membranes.

.4 Reinforced flashing (stripping) membranes shall be installed at all horizontal and vertical transitions, deck penetrations, and protrusions (pipes, curbs, drains, sleepers, etc.). Reinforcement flashing membrane must be a minimum thickness1.5mm (0.060”) and shall be fully adhered to substrates.

6.2.3 Thermoplastic Membranes

6.2.3.1 General

Thermoplastic materials are defined as polymers which soften when heated and harden when cooled. This process is repetitive provided the material is not heated above the point at which decomposition occurs. No cross-linking or vulcanization occurs. In addition to heat welding, some materials can be solvent welded. These welds develop bonding strengths equalling or surpassing the strength of the base materials. Thermoplastic membrane systems that comply RGC Guarantee Standards "E", are installed as fully adhered protected waterproofing assembly, qualify for coverage under the RoofStar Guarantee Program.

6.2.3.2 Composition

Thermoplastic materials used for waterproofing decks on plazas, promenades and terraces in the RoofStar Guarantee Program include only PVC (Polyvinyl Chloride) Membranes:

PVC is a thermoplastic material produced through the polymerization of vinyl chloride, resulting in a relatively hard, resinous material. This material is then formulated with compounds, such as plasticizers and stabilizers, depending on the physical properties required for end use. PVC formulations have been developed to suit numerous commercial and industrial applications.

PVC waterproofing systems are single-ply membranes reinforced with polyester fabric or glass fibres, and in thicknesses usually ranging from 1.2 mm to 2.0 mm, depending on the manufacturer. The membrane is fully adhered and Seams are heat or chemically welded (see manufacturer's requirements).

PVC membrane should conform to CGSB 37-GP-54M 1979, "Roofing and Waterproofing Membrane, Sheet Applied, Flexible, Polyvinyl Chloride" which lists two types of membrane, according to manufacture:

• Type 2 - reinforced

and four classes, according to end use:

• Class A - non-exposed roofing
• Class B - exposed roofing
• Class C - waterproofing
• Class D - flashing membrane asphalt compatible

This standard covers requirements such as "thickness, lap joint strength, permeability, tensile strength, elongation at break, low temperature flexibility, water absorption, resistance to accelerated weathering, dimensional change after stress relaxation, and cone penetration"

PVC membranes should be applied in conformance with CGSB 37-GP-55M 1979, "Application of Sheet Applied Flexible Polyvinyl Chloride Roof Membrane" and the membrane manufacturer's printed instructions.

6.2.3.3 Requirements

.1 PVC (Polyvinyl Chloride) single ply thermoplastic waterproofing membranes shall be reinforced, must be fully adhered to acceptable substrates, and shall be a minimum thickness of 1.5mm (0.060”).

.2 Only proprietary adhesives that are specifically accepted for use by the membrane manufacturer may be utilized to install PVC thermoplastic waterproofing membranes.

.3 Perimeter fixation for membrane securement (mechanical, adhesive, or adhesive tape), installed to manufacturer’s published specifications, is required for all PVC thermoplastic waterproofing membranes.

.4 A reinforced flashing (stripping) membrane shall be installed at all horizontal and vertical transitions as well as deck penetrations (pipes, curbs, drains, sleepers, etc.). Reinforcement flashing membranes must be fully adhered to acceptable substrates and shall be a minimum thickness of 1.5mm (0.060”).

6.2.4 Hot Fluid -Applied, Rubberized Asphalt Membrane

6.2.4.1 General

Fully adhered waterproofing system that utilize hot applied rubberized asphalt compounds, with reinforcement scrims, to form monolithic (seamless) flexible waterproofing membranes.

6.2.4.2 Composition

Single component rubberized asphalt compound installed with reinforcement between two a two layer system. Hot applied rubberized asphalt is fully- adhered to both vertical and horizontal structural surfaces to form monolithic (seamless) flexible waterproofing membrane. Reinforced membrane flashings are installed in Hot applied rubberized asphalt at all deck transitions (wall to deck etc.).

Hot applied rubberized asphalt systems are used for waterproofing on the following applications:

• Waterproofing in an Inverted Assembly

• Split Slab Construction for Plaza Decks

• Terraces, Prominades & Planters

6.2.4.3 Requirements

.1 Hot Fluid-Applied, Rubberized Asphalt membrane systems shall consist of a minimum of two coatings; the first coat shall be a minimum of 90 mils thick and the second coat a minimum of 125 mils thick. A continuous reinforcement scrim of a minimum 1.35 oz/square yard spun bonded polyester fabric shall be firmly embedded into the first coating of hot rubberized asphalt while installation EVT.

.2 All construction joints, minor concrete cracks and deck cover board joints shall receive a pre-treatment of 90 mil thick coating of hot rubberized asphalt and reinforcement fabric prior to the first membrane coating. Coating and fabric reinforcement shall span a minimum of 75mm (3”) beyond the extent of minor cracks and joints.

.3 A reinforced flashing (stripping) membrane, elastomeric, plastomeric or modified bituminous, shall be installed at all major cracks, horizontal and vertical transitions as well as deck penetrations and protrusions ( pipes, curbs, drains, sleepers, etc.). Elastomeric and plastomeric reinforcement flashing membranes shall be a minimum thickness of 1.5mm (0.060”). Modified bituminous reinforcement flashing membranes shall be a minimum thickness of 3mm and be equal to 180g/meter squared polyester or equal strength composite reinforcement.

.4 A layer of asphalt core protection board or SBS modified bituminous membranes shall be installed to all vertical and horizontal surfaces and must be firmly embedded into the second coating of hot rubberized asphalt while above installation EVT. Asphalt core protection board shall be a minimum thickness 4.5 mm (3/16"). Alternately, an SBS Modified bituminous granulated cap sheet, with a sanded bottom surface that is minimum thickness of 3.7 mm and is reinforced with minimum 180g/meters squared polyester or equal strength composite reinforcement may be used as the membrane protection layer. Composite reinforcement (fibreglass/polyester) membranes are strongly recommended when membranes are embedded in hot rubberized asphalt as their physical properties are more dimensionally stable than membranes reinforced with polyester only.

6.3 Protected and Modified Protected Membranes

6.3.1 General

In a Protected Membrane Roof Assembly (PMRA) the membrane functions solely as the waterproofing agent (the requirement for a vapour retarder is eliminated) and the properties of the insulation become more critical. Extruded expanded polystyrene (conforming to CAN / CGSB-51.20-M87, Type 4) is the only commercially produced roof insulation suitable for a PMRA, providing properties such as water resistance (i.e. resistance to water absorption, moisture transfer, and capillary action), resistance to freeze-thaw cycling, and high compressive strength.

A Modified Protected Membrane Roof Assembly (MPMRA) is similar to a PMRA except that a layer of insulation is installed underneath the membrane as well as on top. This may offer cost savings as only the top layer of insulation requires ballast and the bottom layer (mechanically-fastened or adhered) need not be extruded expanded polystyrene and may be tapered to provide slope. The membrane must be located such that the dew point temperature (for the inside air) occurs above the membrane. As a general rule, two-thirds or more of the total thermal resistance (RSI or R value) should be above the membrane, but in all cases the design authority should perform the required psychrometric calculations before designing a roof system.

6.3.2 Roof Decks and Drainage

All roof decks should have proper drainage of the membrane. The RoofStar Guarantee Program recommends the deck have a minimum slope of 1:50 (¼" in 12") towards the roof drains. If, however, an existing roof allows ponding, the insulation is to be applied loose with a permeable fabric over the insulation.

Roof drains are to be located at the low points in the roof. Stone ballast must be prevented from entering drains and gutters. Perforated collars and paving stones are common methods used.

6.3.3 Membranes

Membrane flashings to be extended well above the expected high water level. Refer to the Perimeter Flashing: Membranes section in these Standards for details.

Materials used in the roof assembly must be listed as accepted in the Accepted Materials section of this Manual and conform to applicable material standards CGSB, ULL, CSA, etc.

The roof system must be designed to meet applicable building codes. This may require that 12.7 mm (½") thick gypsum board with siliconzied core and fibreglass facers or equivalent be installed on steel decks. Concrete decks do not require a separate barrier.

6.3.4 Insulation & Filter Mats

Insulation, which is bonded or mopped directly to the roof membrane, is not acceptable.

On all protected and modified protected membrane roofing projects, a filter mat of approved material is to be properly installed between gravel ballast and insulation. The filter mat is required under pre-cast pavers that are used as ballast or walkways.

Filter mats specified must meet the insulation / membrane manufacturer's specifications.

The use of fabric filter mat allows for the use of less ballast. This is achieved by using water permeable fabric between the loose laid insulation boards and the stone ballast. The effect of the fabric is to prevent the displacement of individual boards in case of flotation. The fabric will also prevent fines in the stone ballast from entering the board joints. The fabric must be water permeable and have proven long term weather resistance. It should be strong enough to withstand traffic abuse and prevent displacement of the boards under flotation conditions. The fabric is applied unbonded over the installed insulation. Overlap all edges a minimum of 300mm (12"). If a small piece of fabric is to be used, its dimension shall be at least 2.5 m x 2.5 m (8’ x 8’). Slit fabric to fit over roof penetrations, cut out around roof drains and other openings. Extend fabric up roof perimeter cants and roof protrusions and place it loose under the metal counter flashings.

6.3.5 Ballast

The building structure must be designed to support the weight of the ballast or surface treatment and other superimposed loads on the roof.

Concrete ballast, poured-in-place concrete or concrete topping as ballast or traffic topping is not permitted on RoofStar-guaranteed roofs. Only ballast, which permits easy or reasonable access to the membrane, is acceptable.

Acceptable ballast includes: properly sized gravel, concrete pavers, concrete-topped insulation, etc.

Gravel Ballast: Protected Membrane and Ballasted Membrane Roof Assemblies (EPDM, TPO, PVC, etc.) shall use clean, washed, round or crushed stone, falling within the following gradations:

35 mm (1 ½") - 100 % Passing 25 mm (1") 70 - 100 % Passing 20 mm (¾") 5 - 20 % Passing 12.5 mm (½") 0 - 6 % Passing 5 mm (3/16") 0 - 2 % Passing

Any variance to the above must be accepted by the owner or the owner's representative and be confirmed in writing.

Pedestals: Installation of proprietary (purpose-made) pedestals, with integral spacer ribs for uniform spacing of pavers, or an accepted drainage layer designed to provide vertical separation between pre-cast pavers and substrate or other underlying materials, is mandatory. The use of proprietary drainage boards or pea gravel with filter fabric to provide drainage for unit masonry products (bricks, stone, etc.), is required.

Proprietary (purpose-made) pedestals must have a 3mm (⅛”) integral spacer ribs for uniform spacing between pavers that provide a minimum 12.5 mm (½″) of vertical separation layer for airflow and leveling. The choice of pedestal or drainage layer type is the responsibility of the design authority. Pedestals / drainage layers provide airflow for drying surfaces and assist in leveling. They should not impede the flow of water or air, and should uniformly distribute the dead load of pavers, and other unit masonry products, as well as predicted live loads.

Ballast Requirements for PMRA's

Extruded Polystyrene Insulation Thickness	Required Weight of Stone Ballast	Approximate Depth of Ballast
Standard Measurements
Up to 2"	12 lb./ sq. ft	1 ¾"
3"	17 lb./ sq. ft	2 ¼"
4"	22 lb./ sq. ft	3"
5"	27 lb./ sq. ft	3 ½"
6"	32 lb./ sq. ft	4 ¼"
7"	37 lb./ sq. ft	5"
8"	42 lb./ sq. ft	5 ½"
Metric Measurements
Up to 50 mm	60 kg / m2	40 mm
75 mm	84 kg / m2	60 mm
100 mm	108 kg / m2	75 mm
125 mm	132 kg / m2	90 mm
150 mm	156 kg / m2	105 mm
175 mm	180 kg / m2	125 mm
200 mm	204 kg / m2	140 mm

For an engineered design approach, consult the DOW Chemical TECH SOLUTIONS 508.2 Ballast Design Guide for PMRA roof systems. The resource is provided for reference purposes only.

Resistance to Wind Loads

Roof corners subject to high winds or gusts may scour the stone ballast. Parapets and / or paving slabs can be used where necessary to prevent scouring. In the case of a lightweight PMR roof, with insulation loose applied over the membrane and covered with 50 kg / m² (10 lb. / sq. ft.) of ballast, external pressures due to wind are mostly applied to the membrane.

The membrane will withstand the National Building Code (Canada) calculated pressure if it is properly attached to the deck. In the case of a loose applied membrane it is important to prevent any air infiltration underneath the membrane. Indeed, when air infiltration is restricted, any movement of the membrane will create a vacuum which will neutralize the uplift forces and keep the membrane on the deck.

Tunnel tests done at the National Research Council Canada show that the suction applied to the insulation boards is much lower than the calculated pressure applied to the membrane because of the rapid pressure equalization between the top and the bottom surfaces of the boards. This reduced pressure is insufficient to uplift insulation covered with 50 kg / m² (10 lb. / sq. ft.) of ballast.

7 PERIMETER FLASHING: MEMBRANES

7.1 General

7.1.1 Bituminous Elastomeric & Plastomeric Membranes

1. Membrane flashing (stripping) details (with the exception of low parapets, planter wall pre-curbs, and low door sill details) must be designed to provide a minimum 200 mm (8") sealed height above the waterproofing membrane and not less than 100mm (4”) above the waterproofing system finished surface. Finished surface is defined as the top of the waterproofing assembly, be it concrete pavers, ballast, unit masonry, or growing medium (soil), etc. Refer to Section 9 Construction Drawings
2. All exterior perimeter walls that have waterproofing terminating at or near the top of walls must have membrane flashing (stripping) that overlaps the exterior finish (i.e. wall cladding) by a minimum of 50 mm (2"). On high parapet walls, that are completely flashed with metal, where membrane flashing (stripping) is terminated part way up the wall (without a reglet detail) the remainder of the parapet shall be covered with a flashing underlay of a minimum 40 mils or 1 mm (.040") self-adhered modified bitumen membrane. No. 15 Felt is not acceptable.
3. All membrane flashing (stripping) terminating at cladded (i.e. stucco, siding, etc.) walls must lap under the sheathing membrane and cladding by minimum of 75 mm (3"). All walls and up stands shall be covered with sheet metal base flashings.
4. All membrane flashing (stripping) terminating under a reglet must be sealed to the wall with a compatible mastic and covered with metal flashing that terminates in a reglet.
5. Where a wall or conventional separation / expansion joint detail intersects with a higher wall; the membrane flashing (stripping) must be sealed by reinforcement gussets (membrane saddles) that are formed to reinforce the inside and outside corners.
6. New construction projects must follow proper sequencing. Where waterproofing membrane flashings (stripping) overlaps work by others (i.e. siding, stucco, cladding, , etc.) this work shall be complete prior to the installation of metal flashing or wood blocking must be installed to facilitate the future installation of the exterior wall finishes. When flashing membranes lap under work by others (siding, stucco, glazing, cladding, etc.), the membrane and metal flashings shall be installed prior to any wall coverings. Any variance to proper detail sequencing must be approved by the design authority in writing.
7. Door sill flashing membranes (stripping) may be less than 200 mm (8") in height but shall not be less than 100 mm (4") above the primary waterproofing membrane and must be installed to comply with the following conditions:

• A metal water stop flashing, formed with pan folded, welded or soldered corners must be mechanically attached to inside of door sill framing or opening and be sealed with membrane flashing (stripping).
• Membrane flashing, (stripping) or metal pan sill flashing must be installed at doorjamb framing or opening to a minimum height of 100 mm (4") above door sill framing or opening, prior to installation of doorjambs and doorsills. Membrane gussets must be installed at sill corners.
• Metal pan sill flashings or RGC accepted reinforced liquid flashing systems must be installed wherever clearances preclude the use of membrane flashing (stripping) to seal door sill details.
• Slopes must be provided to direct water away from door sill details. (Overhangs and overflow drains are recommended wherever practical).

8 MEMBRANE PROTECTION

.1 An RGC accepted membrane protection layer(asphalt core board, cap sheet or protection mat), must be installed by the waterproofing contractor, and be compatible with waterproofing membrane. The protection layer shall be installed and secured, as soon as possible, upon completion of waterproofing membrane installation. Construction traffic, by other than waterproofing trade and membrane moisture monitor technicians, is not permitted until the membrane protection layer is completely installed and secured.

9 INSULATION

9.1 Material Selection

Extruded expanded polystyrene (Type 4), conforming to CAN/ULC-S701 (latest edition) with a compressive strength of 240 kPa (35psi) is the only commercially produced insulation suitable for use over waterproofing and protected membrane roofing systems. Extruded expanded polystyrene is available in a 600mm x 1200mm (2'x4') board size, has an aged R value of 5.0 per inch (RSI 0.87) and ranges in thickness' from 25mm (1") to 100mm (4").

For information about XPS insulation, see XPS (Extruded Expanded Polystyrene Foam) in the Essential Elements section of this Manual.

9.2 Layering

Insulation joints shall be offset or staggered a minimum of 300 mm (12") from adjacent layers and rows.

9.3 Application

An accepted drainage layer & filter mat shall be installed on the top surface of extruded polystyrene insulation whenever pavers, gravel ballast, unit masonry or growing mediums (soil) are used as overburdens or wearing courses over waterproofing.

10 DRAINAGE LAYER

10.1 General

Pavers on pedestals promote free subsurface drainage at the membrane the level and are therefore strongly recommended whenever practical. When pedestals are not used as the drainage layer a proprietary geosynthetic drainage core panel is required over waterproofing membranes and is placed above protection boards or extruded polystyrene insulation. Geocomposites and Geosynthetic drainage panels are designed with openings to direct excess subsurface water to deck drains. Proprietary geocomposites and geosynthetic panels must be designed with sufficient compressive strength to support the design load of overburdens as well expected live loads and be acceptable for use by the membrane manufacturer. Geosynthetic drainage cores are typically molded (dimpled) or woven plastic grids, that is a minimum of 9.5 mm (3/8") thick or thicker and is designed to provide uniform support as well as traffic-bearing properties for overburdens and wearing courses.

Filter fabrics (mats) must be installed to a sufficient height at all up-stands, be properly lapped at joints and side laps as well as tightly fitted around all penetrations and protrusions, in order to eliminate the intrusion of overburden or wearing course materials. In order to prevent moisture from being driven into extruded polystyrene insulation drainage board surfaces must not be in direct contact with more than 40% of the insulation board surfaces.

10.2 Material Selection

Only geosynthetic drainage cores and geocomposites with factory laminated filter fabric, which are designed to resist damage from the weight of the specified overburden, are acceptable for use in the RGC Guarantee Program. Refer to the overburden specifications of the project, and membrane manufacturer requirements, when selecting the appropriate material.

10.3 Installation

1. A drainage layer is mandatory between waterproofing membranes, overburdens or wearing courses to provide for free flow of water to drains. Pavers on pedestals provide a subsurface drainage path at the membrane or insulation level and are therefore strongly recommended, whenever practical. Only manufacturer's proprietary purpose made pedestals, with integral spacer ribs for uniform spacing between pavers, that provided a minimum ventilating air space height of 12.5 mm (1/2") are acceptable for use with concrete pavers and other unit masonry products. For waterproofing systems with extruded polystyrene insulation the drainage layer shall be placed on the top surface of the insulation.
2. When manufacturer's proprietary pedestals are not used for drainage a continuous purpose made manufactured geosynthetic drainage core or geocomposites shall be installed under all overburdens or wearing courses. Geosynthetic drainage cores and geocomposites shall be molded (dimpled) or woven plastic grids, shall be a minimum of 9.5 mm (3/8") thick or greater, and provide uniform support as well as traffic-bearing properties for overburdens and wearing courses. Only geosynthetic drainage cores and geocomposites with factory laminated filter fabric, which are designed to resist damage from the weight of the specified overburden, are acceptable for use in the RGC Guarantee Program. Refer to the overburden specifications of the project, and membrane manufacturer requirements, when selecting the appropriate material.
3. Filter fabric (mat) is required for all overburdens that include intrusive materials, growing medium, sand, gravel, mortar, etc. and may be either factory laminated to geocomposites or field installed over geosynthetic drainage cores. Filter fabric shall be installed to a sufficient height at all up-stands, lapped at joints and must be fitted around all penetrations as well as protrusions in order to eliminate the intrusion of overburden and or wearing course materials.
4. In order to prevent moisture from being driven into extruded polystyrene insulations (water vapour transmission) geosyntheticdrainage board and drainage composites surfaces must not be in direct contact with more than 40% of the insulation board surfaces.

11 WEARING COURSE and OVERBURDEN

11.1 General

The design of wearing courses for plaza deck waterproofing systems, fall into two basic categories, accessible and inaccessible. Waterproofing Systems for pedestrian and emergency vehicle traffic on plaza decks are often designed with inaccessible wearing or protection courses. In contrast Protected Membrane Roofing Systems on plaza/terrace decks are almost always designed with accessible wearing courses for pedestrian traffic and utilize pavers on pedestals. Accessible wearing courses are reasonably easy to remove for access to the membrane. Inaccessible wearing courses require demolition for access to the membrane and are usually constructed with cast-in-place concrete protection slabs (split-slab) or brick, tile or stone set in mortar beds. As a result of the potential exorbitant costs of demolition to access membranes under inaccessible wearing / protection courses the performance criteria for these waterproofing systems are higher. Subsequently, additional design requirements and installation standards must be followed in order to provide for an anticipated service life equal to that of the structure and for coverage under the RoofStar Guarantee Program a membrane moisture monitoring system is required in order to identify and locate membrane breaches that may occur during the waterproofing systems service life.

RGC strongly recommends the use of wearing surfaces that permit reasonable easy access to the membrane. Waterproofing systems that incorporate inaccessible protection courses in the design such as poured-in-place concrete, asphalt paving and wearing surfaces units set in mortar beds, etc. must meet additional standard requirements for coverage under the RoofStar Guarantee Program.

11.2 Installation

11.2.1 Accessible Wearing Courses

The use of concrete pavers on pedestals as an accessible wearing course is strongly recommended whenever practical, over all waterproofing systems. Pavers on pedestals provide space for the unobstructed flow of water to drains and permit reasonable easy access to waterproofing membranes.

Unit masonry, brick, tile or stone placed on sand and or gravel beds as well as intensive garden systems are accessible but more difficult to remove than pavers on pedestals in order to provide reasonable access to waterproofing membranes. Subsequently these overburdens require a moisture monitoring sensor grid on top of the waterproofing membrane in order to locate possible breaches in membranes.

11.2.2 Inaccessible Wearing Courses

Inaccessible wearing course designs for pedestrian and emergency vehicle traffic on plaza decks include cast-in place concrete protection slabs (split-slab) and brick, tile or stone set in mortar beds. Subsequently, inaccessible wearing course designs require demolition for access to the membrane and therefore must include an RGC accepted moisture monitoring sensor grid above the membrane to detect as well as locate possible membrane breaches. Moisture scanning grids that are specifically accepted by RGC are listed in Section 2.2 Accepted Materials. Solid cast-in place concrete protection slab (split-slab) and asphalt paving wearing courses (inaccessible) shall incorporate surface score lines (indents) to facilitate cutting for removal of wearing course sections in order to locate possible breaches in membranes. Score lines shall be straight edged grid patterns (squares, rectangles, diamonds, etc.) with indents spaced at a maximum of two (2) metres apart.

12 LANDSCAPING, PLANTERS & OTHER VEGETATED OVERBURDENS

12.1 General

SBS Modified Bituminous membranes used on Landscaped and Vegetated conventionally insulated roofing systems with an overburden 150 mm (6”) or less in depth shall consist of two plies and the top ply (cap) must be a minimum thickness of 3.7 mm on the selvedge edge, with a minimum 180g / meters squared polyester or equal strength combination reinforcement. Thermoset and Thermo Plastic (EPDM, TPO, PVC) single ply membranes used for Landscaped and Vegetated roofing systems shall be fully adhered and a minimum thickness of 1.5mm (0.060").

12.1.1 Definitions

Overburden

In this Manual, “overburden” denotes any manner of material, equipment or installation that is situated on top of, and covering all or a portion of, a roof or waterproofing membrane assembly. This excludes thermal insulation but includes, and is not limited to,

• planters, inclusive of everything they contain;
• vegetated assemblies in trays, mats or other similar containers;
• loose growing media, gravel, sand or any other granular material;
• non-structural water features, inclusive of the water;
• void fill;
• tiles, pavers, supporting pedestals or other similar materials;
• equipment and/or installations, other than those mounted on curbs or structural mounts which are permanently waterproofed with the roof membrane assembly

Extensive Vegetated Roof Assemblies

Roof top gardens having minimal plant species diversity, irrigated only to establish plants, and typically having a soil depth of less than 150 mm or 6 inches.

Intensive Vegetated Roof Assemblies

Roof top gardens with diverse plant species, irrigated for maintenance and typically having a soil depth equal to or more than 150 mm or 6 inches.

12.1.2 Design and Construction Requirements

Roof Systems – Options and Requirements

A conventional roof membrane assembly is not appropriate for all types of roofs supporting overburden. For example, overburden weight, and hydrostatic pressure exerted because of certain types of overburden, demand different materials and design approaches to ensure membranes do not fail. Therefore, where

• the designed overburden of the roof assembly (excluding plants) equals or exceeds 150 mm (6”) in depth, or
• the point-loading of overburden equals or exceeds 138 kPa (20 psi); or
• moveable planters or equipment/installations on a roof each weigh 90 Kg (200 lbs) or more

the roof must be designed and constructed to comply with all the requirements for a Protected Membrane Roof assembly (insulated above the membrane); under these circumstances, conventionally insulated roof assemblies (insulated beneath the membrane) are not permitted under the RoofStar Guarantee Program. Furthermore, both a Moisture Survey Scan of the installed membrane assembly and a permanently installed electric leak detection system are mandatory (for leak detection system requirements, refer to the RoofStar Guarantee Standards for Waterproofing Plazas, Promenades and Terraces). EPDM roof membranes are therefore excluded from these applications.

The cost of removal and re-installation or replacement of any such equipment, installations, planters, overburden (or services and connections associated with them) is the sole responsibility of the building owner, whether for the purpose of investigating a leak or conducting warrantable repairs to the membrane.

Some types of overburdens are not permitted on conventionally insulated roof systems. Use the chart below to determine whether or not your overburden design is appropriate for a conventional roof. If it isn’t, the roof must be designed as a Protected Membrane Assembly Roof and will require a leak detection system.

Roof Assembly Type	Overburden characteristics
	< 90 kg ea. object	= / > 90 kg ea. object	< 138 kPa (20 psi) point load	= / > 138 kPa (20 psi) point load	< 150 mm (6") depth	= / > 150 mm (6") depth
CONVENTIONAL ROOF SYSTEM
Integrity Scan	Not available for Conventional Roof Systems under the RoofStar Guarantee Program
Leak Detection System	Not available for Conventional Roof Systems under the RoofStar Guarantee Program
PROTECTED MEMBRANE ROOF SYSTEM		Required		Required		Required
Integrity Scan		Required		Required		Required
Leak Detection System		Required		Required		Required

= Permissible (but not required)

= Not Permissible

For further requirements concerning leak detection for Rooftop Gardens, Planters & Occupied Spaces, see 10.7 Membrane Moisture Surveys and Electric Leak Detection.

12.2 Membrane Protection

Protection for roofing membranes is required during the installation and maintenance of landscaping, extensive and intensive vegetated (green) roofing installations. The minimum membrane protection must be installed by the roofing or waterproofing contractor and shall be 3 mm (⅛") asphalt core protection board or 25 mm (1") minimum extruded polystyrene insulation plus filter mat, root intrusion barrier, and drainage layer. Tightly butt all protection and insulation boards, overlap all filter mat seams and seal all laps of roof intrusion barriers to RoofStar Guarantee Standards and manufacturer’s installation instructions.

Only RoofStar-accepted SBS Modified Bituminous, Thermoset and Thermoplastic roofing membranes that are specifically accepted by the membrane manufacturer for use on Landscaped and Vegetated (green) roof systems qualify for coverage under the RoofStar Guarantee Program.

The Membrane Manufacturer and RoofStar Guarantee Program must confirm acceptance of other alternative protection systems or components in writing. Damage to membranes and flashings that results from the use of plants with aggressive root structures, (Bamboo, Willow etc.) for landscaped and green (vegetated) roof systems, is not the responsibility of the RoofStar Guarantee Program and is specifically not covered under the RoofStar Guarantee. For additional information refer to the latest addition of the British Columbia Landscape Standard, Green Roof Section.

Conventionally insulated roof assemblies are required to have a minimum 12.5mm (½") adhered RoofStar-accepted gypsum overlay board, and insulation boards with a minimum compressive strength of 20 psi, under the roof membrane for extensive vegetated systems (with depth less than 150 mm, or 6"). Intensive vegetated systems (with depth equal to or greater than 150 mm, or 6") are not permitted over conventionally insulated roof systems.

12.2.1 Root Barriers & Separation Zones

Proprietary root intrusion barriers must be acceptable to the roof membrane manufacturer and appropriate for the vegetation system installed. Polyethylene or polypropylene sheeting used as a root barrier shall be a minimum thickness of .2mm (8mils). Root Barriers shall be sheets or boards installed in a continuous plane above the roof membrane, carried up the inside of soil retention perimeters (separation zones), and must be installed with sealed laps and seams as per manufacturer's instructions.

Separation Zones that are free of growing medium and vegetation are required around all roof perimeters, up-stands, drains, penetrations, mechanical equipment, expansion joints, etc. Zones must be a minimum of 300 mm (12”) wide and constructed with curbs or other physical barriers that separate and facilitate drainage. Physical barriers must be placed above the membrane protection layers and must not be attached through or penetrate the roof membrane.

12.2.2 Drainage

A drainage layer is required. Specialized proprietary drainage products must be acceptable to the membrane manufacturer.

12.3 Planter Design & Waterproofing

Non-structural planters placed over landscaped deck and roofing membranes, with an appropriate protection layer, are strongly recommended whenever practical.

12.4 CSA A123.24 and Wind Uplift

All vegetated roof systems using a modular system are required to meet CSA A123.24 “Standard test method for wind resistance of modular vegetated roof assembly” (latest edition).

12.5 Overburdens

12.5.1 Extensive Vegetated Roof Assemblies

Where Extensive Vegetated Roof Assemblies are installed as part of the roofing specification and / or contract, the costs for removal and replacement of soil to access the membrane, to investigate or repair leaks in the membrane, are included in the RoofStar Guarantee coverage. However, the removal and replacement of plants, irrigation lines and or equipment, electrical lines, landscape and decorative features such as concrete pads, statues, planters, large rocks, etc., to investigate or repair leaks in the membrane, is not included, and is the responsibility of others. Subsequently, such access shall be provided and/or paid for by others.

12.5.2 Intensive Vegetated Roof Assemblies

Intensive Vegetated Roof Assemblies installed as part of the roofing specification and/or contract are permitted on conventionally insulated membrane roof assemblies provided the depth of the growing medium does not exceed 150 mm (6″).

When an Intensive Vegetated Roof Assemblies with growing medium greater than 150 mm (6”) forms part of the roofing specification and/or contract, the roof must be designed and constructed to the RoofStar Guarantee Standards for a Protected Membrane Roof assembly (see 10.1.2 above). Consequently, the removal and replacement of such overburden is the responsibility of the others, and such costs do not form part of the coverage under a RoofStar Guarantee.

12.5.3 Planters

Structural planters that incorporate pre-curb or start-up curbs for walls that are completely sealed with membrane and are a minimum of 100 mm (4") in height, as detailed in Construction Detail D1.7.6-5 Curbs & Sleepers (Pre-curb for Planters), qualify for RoofStar Guarantee coverage. Waterproofing liners in planters with structural walls, concrete curb or other materials, that do not incorporate pre-curbs shall be isolated and separated from the guaranteed roofing membrane and are specifically not accepted under the RoofStar Guarantee.

Non-structural planters placed over landscaped deck and roofing membranes, with an appropriate protection layer, are strongly recommended whenever practical. Structural planters that incorporate pre-curb or start-up curbs for walls that are completely sealed with membrane and are a minimum of 100 mm (4") in height, as detailed in D1.7.6-5 Curbs & Sleepers (Pre-curb for Planters), qualify for RoofStar Guarantee coverage.

Waterproofing liners in planters with structural walls, concrete curb or other materials, that do not incorporate pre-curbs shall be isolated and separated from the guaranteed roofing membrane and are specifically not accepted under the RoofStar Guarantee. Conventionally insulated roof assemblies are required to have a minimum 12.5mm (½") adhered approved RoofStar-accepted gypsum overlay board, and insulation boards with a minimum compressive strength of 20 psi, under the roof membrane for extensive vegetated systems (less than 150 mm, 6" in depth). Intensive Vegetated Roof Assemblies in excess of 150 mm (6") or more in depth are not permitted over conventionally insulated roof systems.

12.6 Walkways and Warning Zones

When primary roof membranes of contrasting colour are used for warning zones, membrane end lap off sets and ply side lap directions must be maintained. Staggered membrane end lap offsets may be positioned below primary roof membranes that are used for warning zones.

Where walkways are employed, they must be designed to facilitate drainage of water. To promote drainage, use accepted concrete-topped XPS insulation panels, or pavers located on purpose-made pedestals. When pavers are used as the walkway material, they must be spaced no closer than 3mm (1/8″) and must be supported by non-abrasive pads or proprietary pedestals providing a minimum of 12.5 mm (1/2″) of vertical separation layer for airflow and levelling. The choice of pedestal or drainage layer type is the responsibility of the design authority. Pedestals provide airflow for drying surfaces and assist in leveling. They should not impede the flow of water or air, and should uniformly distribute the dead load of pavers and predicted live loads.

A design authority or membrane manufacturer may specify a proprietary walkway protection system or warning zone membrane over the primary roof membrane. Walkway and warning zone materials are not part of the roofing membrane assembly but are typically accessory products that are placed over completed roof membranes. Subsequently the type and performance of any walkway or warning zone material is specifically excluded from coverage under the RoofStar Guarantee, as is any detrimental effect the materials may have on the roof system.

12.7 Membrane Moisture Surveys and Electric Leak Detection

12.7.1 General

A Membrane Moisture Survey and permanently installed electric leak detection system is mandatory for all roofs that must be designed and installed to meet the requirements for a RoofStar Guaranteed Protected Membrane Roof assembly (see 10.1).

12.7.2 Flood Testing

Flood Testing is not a recommended practice but is at the discretion of the design authority or owner. If flood testing is required to water test waterproofing membranes, testing shall be conducted prior to installation of insulation and overburdens and be performed to ASTM D5957 - 98.

12.7.3 Application

12.7.3.1 Moisture Scan Survey

Membrane moisture survey scans must be performed on all waterproofing membrane systems by an independent Moisture Detection Company that is specifically accepted by the RoofStar Guarantee Program.

12.7.3.2 Leak Detection Systems

Only electric leak detection systems (utilizing high or low voltage) accepted for use in the RoofStar Guarantee Program may be installed and monitored on waterproofing systems designed and accepted by the RoofStar Guarantee Program.

A Membrane Moisture Survey and an installed electric leak detection system is not required on PMR or MPMR roof systems when the roof system is designed and constructed with

• overburden not exceeding 150 mm (6”) in depth, or

• moveable planters or equipment/installations on a roof each weighing less than 90 Kg (200 lbs); or

• standard concrete pavers on pedestals

Regardless of the accepted leak detection technology employed, the leak detection system must provide detection capabilities for the entire affected deck surface and extend leak detection a minimum of 50 mm (2") vertically from the water plane at

• all transitions;

• any point along the entire deck perimeter; and at

• protrusions.

Where the electric leak detection system of choice utilizes a sensor ribbon installed on the waterproofing membrane in a grid pattern, the ribbon spacing shall be no less than two (2) metres in any direction for waterproofing systems covered by the Overburden.

12.7.4 Leak Detection for Sensitive Occupied Spaces

Designers are strongly encouraged to consider specifying an insulated (PM) membrane system and mandatory leak detection protection for a RoofStar Guarantee when the occupied space below a roof area contains, or will contain,

• highly sensitive equipment or contents (e.g. hospitals, art galleries), or
• electronic systems (e.g. communications or data centres)

Criteria for evaluating the sensitivity of building interiors is left to the Design Authority.

13 MEMBRANE MOISTURE SURVEYS & MONITORING SENSOR GRIDS

13.1 General

A membrane moisture scan survey and report that confirms the water tight integrity of waterproofing systems is a mandatory requirement of the RoofStar waterproofing guarantee program, for all waterproofing systems, prior to installation of overburdens or wearing courses. Membrane moisture survey scans must be performed by an independent moisture detection company, whose moisture detection system has been reviewed by the RCABC Technical Committee and deemed to be suitable for inclusion in the RoofStar waterproofing guarantee program. In addition, moisture monitoring sensor grids (conductance scanning grid) are mandatory and shall be installed on the top surface of all waterproofing membrane systems designed with inaccessible overburdens and wearing courses. The exceptions that do not require moisture monitoring sensor grids are pavers on pedestals and gravel ballast to a maximum 100mm (4") thick . Moisture monitoring sensor grids shall be installed prior to installation of overburdens or wearing courses and may be placed over protection boards or SBS membranes that have been set in hot fluid-applied modified asphalt. (Refer to RoofStar Guarantee Standards E membrane moisture scan survey and report.)

13.2 Flood Testing

Flood Testing is not a recommended practice but is at the discretion of the design authority or owner. If flood testing is required to water test waterproofing membranes, testing shall be conducted prior to installation of insulation and overburdens and be performed to ASTM D5957 - 98.

13.3 Application

A moisture scan survey and report which confirms the water tight integrity of membranes is mandatory for all waterproofing systems prior to installation of inaccessible overburdens or wearing courses that are difficult to remove. Membrane moisture survey scans must be performed by an independent Moisture Detection Company that is specifically accepted by RGC.

With the exception of pavers on pedestals, gravel ballast to a maximum of 75mm (3”) thick), and soil or extensive growing mediums less than 200mm (8”) in depth a moisture monitoring sensor grid (conductance scanning grid) is mandatory and shall be installed on the top surface of all waterproofing membrane systems designed with overburdens and wearing courses. Moisture monitoring sensor grids shall be installed prior to installation of overburdens or wearing courses and may be placed over protection boards or SBS membranes that have been set in hot fluid-applied modified asphalt.

13.3.1 Accessible Wearing Courses

Scanning sensor grids on waterproofing systems with reasonably accessible overburdens such as unit masonry, bricks, stone and pavers on sand or gravel beds as well as soil or intensive growing mediums more than 200mm (8”) in depth, shall be spaced on a grid of a maximum of three (3) meters in any direction. The scanning sensors grid must cover the entire deck surface, shall be carried to a minimum of 50mm (2”) in height at all vertical transitions as well as deck perimeters, penetrations and protrusions.

13.3.2 Inaccessible Wearing Courses

Scanning sensor grids on waterproofing systems with inaccessible overburdens such as concrete pours (split –slab), asphalt paving, unit masonry ( bricks, pavers and stone) set in mortar beds shall be spaced on a grid of a maximum of two (2) meters in any direction. The scanning sensors grid must cover the entire deck surface, shall be carried to a minimum of 50mm (2”) in height at all vertical transitions as well as deck perimeters, penetrations and protrusions.

14 PENETRATIONS and DRAINS

14.1 General

Deck penetrations, pipes, curbs, drains, etc. shall NOT be installed less than 200 mm (8") from one another or the base of walls and other construction details unless specifically authorized by the inspection agency as a special condition. These items are to be located by others.

14.2 Strip-in Curbs

Curb mountings for all venting units, equipment, pipes and cables on waterproofing decks are strongly recommended. Curbs are to be supplied and installed by others. Curbs are to be a minimum 200 mm (8") sealed height above the waterproofing membrane and not less than 100mm (4”) above the waterproofing system finished surface (overburden). Only purpose made non-ferrous metal strip-in type vents will be permitted for use with waterproofing systems.

14.3 Pipe & Cable Flashing

Pipes, cables and multiple roof penetrations, including grouped pipes and or cables, must incorporate purpose-made weather head seals. Purpose-made multiple penetration weather head seals must provide a positive weather seal by use of metal hoods, manufacturer's proprietary rubber based friction seals, mechanical clamps or gooseneck type designs. Gum boxes or pitch pans are not permitted for use with waterproofing systems.

14.4 Drains and Scuppers

1. The use of bi-level drains with adequate openings for both surface and subsurface drainage are mandatory for all inaccessible waterproofing systems that utilize interior drainage systems with low permeable wearing courses (poured concrete, bricks, unit masonry and stone set in mortar beds).
2. Membrane flashing reinforcement is required for drains and other roof accessories and is to be installed as per waterproofing membrane manufacturer's published application instructions.
3. When cast-iron drains are used; a sump receiver and under-deck clamp must be provided and installed by the trade supplying the deck drain.
4. All flange type drains as well as flow through wall drains and scuppers shall be constructed of non-ferrous materials.
5. On all waterproofing projects all drains connected to internal piping shall be connected by mechanical compression type seals only. "O"-rings, mastics and caulking are not acceptable methods to seal drains to internal piping.

15 PERIMETER FLASHINGS: METAL

15.1 General

All protrusion and penetration flashings, vents, curbs, sleepers, pipes cable, drains, etc. shall NOT be installed LESS than 200mm (8") from the base of walls, cants or installed equipment, protrusion or other penetration flashings.

Metal base flashing shall be kept approximately 25 mm (1") above gravel to prevent immersion in water with the exception of protected and modified protected waterproofing systems.

Gravel-stop type flashings may be used, provided manufacturer's printed instructions are followed The exceptions are overflow drains and roof scuppers that are installed through walls. These items are to be located by others.

Sheet metal flashings are designed to divert water away from the membrane flashing termination, usually onto the roof. The metal flashing also protects the membrane from deterioration due to the elements and from mechanical damage. The metal flashing is not a waterproofing membrane, therefore the roofing membrane should be continuous under the metal (see Metal Flashing Details).

For further details, the Sheet Metal and Air Conditioning Contractors National Association, Inc. (SMACNA) publishes a reliable reference for the proper design and installation of architectural sheet metal. The Architectural Sheet Metal Manual is available from:

Sheet Metal and Air Conditioning Contractors National Association, Inc.

c/o British Columbia Sheet Metal Association

156 - 4664 Lougheed Hwy Burnaby, B.C. V5C 5T5 (604) 299-4641

15.2 Material Selection

The following minimum gauges and / or weights of commonly used metals or alloys will be applied to all projects under the Guarantee Program. The length of metal flashing shall be limited to a maximum of 3.04 m (10').

GALVANIZED STEEL: 0.50 mm (0.0196", 26 gauge) galvanized steel sheet, conforming to ASTM A653 / A653M-06 CS Type B, Z275 (G90) coating. Thickness tolerance as per ASTM A924/A924M-06 ±0.08 mm (0.003") for sheet widths not exceeding 1500 mm (60").

ALUMINIUM – ZINC ALLOY COATED STEEL: 0.50 mm (0.0196", 26 gauge) aluminium-zinc alloy coated steel sheet, conforming to ASTM A792/A792M-06 CS Type B, AZM150 (AZ50) coating. Thickness tolerance as per ASTM A924/A924M-06 ±0.08 mm (0.003") for sheet widths not exceeding 1500 mm (60").

ALUMINIUM: 0.80 mm (0.032", 20 gauge) aluminium sheet, utility quality to CSA HA Series - 1975, plain or embossed finish. Maximum thickness tolerance variation ± 0.06 mm (0.0025") based on 1200 mm (48") wide sheet.

STAINLESS STEEL: 0.38 mm (0.014", 28 gauge) stainless steel, Type 302, 304, 316, 2B finish to ASTM A167-82. Maximum thickness tolerance variation ± 0.04 mm (0.0015") based on 1200 mm (48") wide sheet. COPPER: 0.56 mm (0.022", 16 oz.) copper sheet, cold rolled roofing copper to ASTM B370-81. Maximum thickness tolerance variation ± 0.09 mm (0.0035") based on 1200 mm (48") wide sheet.

ZINC: 0.80 mm (0.031") zinc Sheet conforming to European standard EN 988-1996. Maximum thickness tolerance variation ± 0.03 mm (0.0012").

Specifying authorities should indicate the type and gauge of metal required, as well as the qualifying standards. The reference standard for gauges is USS REV (metric in mm).

15.3 Attachment

The use of concealed in-seam fasteners is required. Any fastening of metal flashings on the top of parapet surfaces is strongly discouraged and is not permitted as the only attachment method.

If top-surface fastening must be used because of a specific job site condition, only appropriate screw-type fasteners with neoprene washers may be used. Nails are not acceptable. The outside and inside face of metal cap flashing must be attached with cladding fasteners (screws), and/or concealed clips. Continuous and discontinuous concealed clips and or cladding screw fasteners or a combination of these attachment methods are acceptable to secure metal cap flashing. No fastening of flashing is permitted within 87.7 mm (3-1/2") of the roof surface. Note: Cladding fasteners or concealed clips are not required on the inside face of roof edge cant strip details.

Cladding fasteners (screws) with gasketed washers, used as exposed fasteners for metal flashing, must be No. 8 or better, made of metal compatible with and corresponding in colour to, the flashing material being installed. Nails are not acceptable as exposed fasteners. The minimum number of cladding screws used to face fasten metal cap flashing shall be three (3) fasteners equally spaced (±10%) between seams of flashing formed from 3000 mm (10 ft.) metal stock and a minimum of two fasteners equally spaced (±10%) between flashing seams formed from 2400 mm (8 ft.) metal stock. Concealed clips, both continuous and discontinuous, shall be formed from the same metal type as the flashing being secured and be minimum 24 gauge in thickness. In addition, concealed clips are to be fastened as close to the bottom edge (hook) as practical but must not be fastened further than a maximum of 75 mm (3") from the bottom edge (hook). Concealed clips must engage drip or safety edges by a minimum of 12.7 mm (1/2").

Continuous Concealed Clips are to be attached with appropriate corrosive resistant fasteners spaced at a maximum of 300 mm (12") o/c. Discontinuous Concealed Clips shall consist of a single clip centred between the seams of each length of metal flashing. Clips shall be a minimum of 1000 mm (40") in length for flashing formed from 3000 mm (10 ft.) metal stock and a minimum 800 mm (32") in length for 2400 mm (8 ft.) metal stock. Discontinuous clips for shorter flashing lengths shall be approximately 1/3 the length of the metal flashing but not less than 100 mm (4") in length. Corrosive resistant fasteners for clips, to be spaced a maximum of 300 mm (12") o/c.

15.4 Curb Heights

On all waterproofing assemblies the minimum curb height (equipment curbs, vent curbs, etc.) shall be 200 mm (8") above the roof surfacing. Surfacing is defined as the top of the waterproofing assembly, regardless of the type of wearing course.

15.5 Seams

Standing seams and S-lock seams are both acceptable.

Seaming of inside corners shall be carried to the base of the cant or the base of the metal. S-locks shall be fastened before the insertion of successive flashings. .2 Lap seams are acceptable only where the vertical run on the inside corner is less than 100 mm (4").

When the vertical height exceeds 300 mm (12"), standard seaming practices will be followed. When cants are not used on curbs, standard seaming practices (standing seams) shall be followed at all times, with the exception of the vertical flashing portion that is lapped to fit under counter flashing or equipment flanges.

For roof curb-flashing seams ( e.g. equipment, skylights, etc.), which do not exceed 300 mm (12") in height, lap-type seams may be used on the vertical portion provided standing seams are used in the cant area.

The design authority shall choose and specify the seaming system.

15.6 Cap Flashings, Base Flashings and Reglets

The top surface of walls (parapets, expansion joints, firewalls, roof dividers, etc.) wider than 100 mm (4" nominal) shall be constructed to provide positive slope to drain and be covered with metal cap flashing. Provide a reglet for all flashings terminating in concrete or masonry walls. When wall flashing terminates in a reglet, typically on high parapet walls, a coping flashing is required at the top of the parapet wall (see Metal Flashing Details). On new construction projects reglet and sloped wood blocking at top surface of concrete or masonry walls are to be installed by others.

Metal base flashings are required on all walls and curbs on roof systems that utilize gravel ballast filter mats, and must “kick out” minimum 50 mm (2") over insulation and filter fabric.

Reglet must be 200 mm (8") minimum to 300 mm (12") maximum above the waterproofing surface. Waterproofing surface is defined as the top of the waterproofing assembly, be it membrane or ballast.

In the case of multi-wythe masonry, composite walls, or parapets, and where not restricted by seismic codes, continuous flexible thru-wall flashings must be supplied and installed (by others), at the next course above the reglet or, alternatively, the inside of the parapet wall must be completely flashed or cladded.

Metal base flashing is required on all vertical surfaces, walls, curbs, etc. when hot asphalt is used to adhere stripping (flashing) membranes.

Gum edge or gum lip flashings should be avoided in all circumstances. If job conditions allow for no other alternative, written permission from the RoofStar Guarantee Program (Technical Manager) for use of gum edge flashing must be obtained (also called surface reglet)

15.7 Flashing on Stucco Walls

On stucco-faced walls, only 2-piece flashings are permitted. The upper piece, retaining the stucco, must have a vertical flange to extend behind stucco and building paper. Stucco stops are not considered metal counter flashings.

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Waterproofing Plazas, Promenades and Terraces

Accepted Materials