RoofStar Guarantee Standards for Asphalt Shingle Systems

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RoofStar Guarantee Standards for Asphalt Shingle Systems

How to use the Guarantee Standards section

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.

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.

Content in this section is colour-coded according to four classes:

Guarantee Standards
Guiding Principles
Reference materials

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For definitions of these terms of reference, click here.

1 Asphalt Shingle Application: STR-AS (Standard or Steep Slope)

STANDARD OR STEEP SLOPE APPLICATION

1:3 (4" in 12") or steeper)

This specification is intended to meet or exceed the requirements of the Building Code and shall be installed to CAN3-A123.51-M85 (R2006) Asphalt Shingle Application on Roofs 1:3 and steeper.

1.1 MATERIALS

1.1.1 General

.1 Asphalt Shingles: manufactured to A123.1-05/A123.5-05 (R2010) for fibreglass felt shingles.
.2 Nails: large-head corrosion resistant roofing nails conforming to CSA B111; electro-galvanized, hot-dipped galvanized steel, aluminum, or stainless steel.
.3 Roofing Cement: asphalt-base conforming to CGSB 37-GP-5Ma.
.4 Eave Protection - RoofStar-accepted self-adhered, rubberized asphalt sheet material, or RoofStar-accepted proprietary underlayments that meet or exceed the requirements for CSA A123.3-05 (2010).
.5 Valley Materials: sheet metal and / or minimum 3.7 mm thick SBS granulated modified bituminous membrane conforming to CAN / CGSB 37-GP-56M.
.6 Lap cement conforming to CGSB 37-GP 4M.
.7 Underlayment: A minimum of No. 15 non-perforated asphalt saturated felt conforming to CSA A123.3 M1979 and / or ASTM D226-95, and as acceptable under the RoofStar Guarantee Program (see Eave Protection & Underlayment for shingle roofing).
.8 Water diverter Flashing: Minimum 0.56 mm (26 gauge) galvanized iron, 0.80 mm (0.032") aluminum, or 0.56 mm (0.0216", 16 oz) copper.
.9 Cladding Screws: Minimum No. 8 (⅛") gauge with rubber gasket grommet or washer made of metal compatible and corresponding in colour to metal flashing material.

1.1.2 Sheet Metal (Flashing)

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").

1.2 APPLICATION

Asphalt Shingles shall be installed to CAN3-A123.51-M85 (R2006) Asphalt Shingle Application on Roofs 1:3 and steeper.

1.2.1 Deck Requirements

.1 Wood decks shall be constructed of plywood, securely fastened to supports. Oriented strand or non-veneer panels are not recommended as acceptable deck materials.
.2 Plywood for roof decks shall conform, as a minimum, to the requirements of the Building Code; but it is strongly recommended, for better nailing and less deflection, that the following be used: 12.7 mm (½") thick when supported at 400 mm (16") o/c or 15.9 mm (58") thick when supported at 600 mm (24") o/c (refer to RoofStar Guarantee Standards in Roof Decks).
.3 Knotholes and cracks in decks shall be considered defects and must be covered with sheet metal nailed in place.
.4 Wood decks constructed of shiplap and dimensional lumber shall be overlain with sheathing that conforms to CSA 0151-04, Canadian Softwood Plywood, Grade C or better; or CSA 0121-M 1978 (R2003) Douglas Fir Plywood, Grade C or better. Minimum thickness to be 9.5 mm (38"). Refer to 2.2.11 Wood deck overlay sheathing (Non-Structural) for sheathing overlay installation requirements.
.5 The use of non-veneered panels in steep slope applications with asphalt shingles applied directly to the deck is not recommended by the RoofStar Guarantee Program, as there can be an increased chance of deck deflection between supporting trusses or rafters.
.6 When plywood or non-veneer (OSB or wafer) panels fastened to metal Z-bars (girts) are used for roof sheathing (decking), sheathing must be a minimum thickness of 15.9 mm (5/8"). In addition, asphalt shingle roofing nails must not penetrate the roof sheathing when metal Z-bars (girts) are used as the attachment substrate for roof deck sheathing.
Note: For re-roofing over old deck, deck must comply to specifications as for new work (refer to RoofStar Guarantee Standards for Wood Decks).

1.2.2 Tie-in (Re-roofing or Building Additions)

Where a new roof is tied-in to an existing roof, the two areas must be isolated and separated by a curb joint properly constructed a minimum height of 125 mm (5”), attached to the structure and properly flashed.

1.2.3 Eave Protection and Underlay

.1 Acceptable eave protection consists of one continuous width of accepted self-adhesive rubberized asphalt sheet.
Apply on the roof deck, extending from the edge of the roof a minimum distance of 915 mm (3′) up the roof slope to a line not less than 300 mm (12″) inside the inner face of the exterior wall. In high snow regions, extend the eave protection not less than 600 mm (24”) inside the inner face of the exterior wall. Eaves protection membrane is to be carried up all abutments (walls, skylights, etc.) a minimum of 125mm (5″).
Eave protection is not required:
  1. over unheated garages, carports, and porches, or
  2. where the roof overhang exceeds 915 mm (3′) measured along the roof slope from the edge of the roof to the inner face of the exterior wall.
Horizontal runs of eave protection must be positively lapped at least 50 mm (2″) and end laps (vertical joints) must be at least 150 mm (6″). Where negative (backward) laps are unavoidable, laps must be at least 150 mm (6”), and seams must be roller-pressed and sealed with a compatible mastic along the seam edge.
.2 Acceptable underlay may include any of the following:
  • At least one ply of 15 lb. non-perforated asphalt saturated felt
  • RoofStar-accepted synthetic underlayment
  • RoofStar-accepted self-adhering eave protection
For materials acceptable under the RoofStar Guarantee Program, see Eave Protection & Underlayment.
Apply underlayment to all roof decks in shingle fashion, fastened in accordance with the manufacturer’s published instructions and acceptable fasteners.
Horizontal runs of underlayment must be positively lapped at least 50 mm (2″) and end laps (vertical joints) must be at least 150 mm (6″). Where negative (backward) laps are unavoidable, only a RoofStar-accepted self-adhering underlayment may be used. Negative laps must be at least 150 mm (6”), and seams must be roller-pressed and sealed with a compatible mastic along the seam edge.
Underlayment is to be carried up all abutments (walls, skylights, etc.) a minimum of 125mm (5″).
Felt underlays and asphalt shingles must be applied on the same day. To prevent wrinkling, let felt relax before installing.

1.2.4 Shingles: Field Application

.1 Strip or Standard Shingle - Minimum slope 1:3 (4" in 12"). First course shall consist of shingles of the same type used for the roof applied with tabs facing up the slope when permitted by the manufacturer,or use the starter assembly dictated by the manufacturers printed instructions. Each shingle shall be applied with a minimum of four nails per shingle.
All shingles shall be applied with a maximum exposure as recommended by the manufacturer. All vertical and horizontal lines shall run true. Each shingle shall be sealed with a manufacturer's accepted asphalt adhesive sealing strip, or each tab shall be manually gum tabbed.
.2 Lock Shingles - Minimum slope 1:3 (4" in 12") Starter course shall consist of an additional course of strip shingles, lock shingles, or Type M mineral surface, minimum width of 335 mm (13"). Each shingle shall be applied with a minimum of two nails. All trimmed or partial shingles shall be hand gum-tabbed at terminations like gable edges, valleys, vents, curbs, etc.
.3 Laminated or Architectural Shingles – Minimum slope 1:3 (4" in 12"). Starter course shall consist of Manufacturers’ proprietary starter shingles or same type shingles with the exposed (bottom) portion cut off below the seal strip or cut to achieve sufficient head lap and applied to manufacturers’ printed application instructions. Each shingle shall be fastened with a minimum of four nails per shingle. Nails must penetrate through both layers of laminated shingle at overlap areas within the nail zone. High nailing is not an accepted practice for asphalt shingle application covered under the RoofStar Guarantee Program.
Note: All types of shingles shall be applied with a maximum exposure and minimum shingle course off sets as recommended by the manufacturers’ written application instructions. All vertical and horizontal lines shall run true. Each non-locked type shingle shall be sealed with a manufacturer's accepted asphalt adhesive sealing strip, or each tab shall be manually gum tabbed.
Note: All types of shingles are to overhang the fascia sufficiently to lead water to eaves trough, nominally 37 mm (1½").

1.2.5 Valleys

All valley types must have an accepted eaves protection membrane as underlayment

.1 Open valleys shall be flashed with sheet metal not less than 600 mm (24") wide or one layer of not less than 3.7 mm thick SBS, granulated, modified bituminous membrane, 1 m (39") wide centred in the valley and fastened with nails spaced not more than 450 mm (18") located 25 mm (1") away from the edges. Cut and trim all points of valley shingles. Open valleys are the only style permitted for lock type or laminated asphalt shingles.
Optional Open Valley Application Method: Laminated Shingles
The vertical course open valley application method is acceptable for use only with laminated asphalt shingles and only when the asphalt shingle manufacturer recommends or accepts this optional open valley application method. Apply one row of shingles laid end to end vertically up each side of the installed valley materials with the shingle butt edge placed toward the centre of the valley, using chalk lines for guidance. Fasten shingles along manufacturers’ fastener line with a minimum of four fasteners per shingle. Field shingles (uncut) are laid perpendicular to the roof slope over vertical shingles on both roof planes. Ensure that no nails are located any closer than 150 mm (6") from the butt edge of vertical shingles and that all edge joints between vertical shingles are completely covered or overlaid with field shingles. Shingle course offsets shall be applied as recommended by the manufacturers’ written application instructions.
.2 Woven valley (sometimes used for standard slope shingle application) shall consist of a minimum 915 mm (36") wide layer of RoofStar-accepted eaves protection membrane, centred in the valley and nailed in such a manner to hold firmly in place until the shingles are applied. Note: Woven valleys are not acceptable when interlocking or laminated shingles are used.
Valley shingles are laid over the lining by either:
  • applying them on both roof areas at the same time, weaving each course in turn over the valley; or
  • covering each roof area first to a point approximately three feet from the centre of the valley and weaving the valley shingles in place later.

When following the first procedure, the first course is laid along the eaves of one roof area up to and over the valley, extending it along the adjoining roof area for a distance of at least 300 mm (12"). The first course is then laid along the eaves of the intersecting roof area and is extended over the valley on top of the previously applied shingle. Succeeding courses are then laid alternately, first along one roof area and then along the other, weaving the valley shingles over each other. Make sure that the shingles are pressed tightly into the valley and nailed in the normal manner, except that no nail is to be located closer than 150 mm (6") to the valley centre line, and that two nails are to be located as shown at the end of each terminal strip.

Closed cut valleys shall consist of a minimum 915 mm (36") wide layer of RoofStar-accepted eaves protection membrane centred in the valley without bridging and nailed to be held firmly in place until the shingles are applied. Closed cut valley may only be used on roof slopes exceeding 1:3 (4" in 12") and only if permitted in writing by the shingle manufacturer. Closed cut valley may not be used with inter-locking or laminated asphalt shingles.

The first course of shingles is laid along the eaves of one roof area up to and over the valley, extending it along the adjoining roof section for a distance of at least 300 mm (12"). Follow the same procedure when applying succeeding courses of shingles on this roof area. Make sure that the shingles are pressed tightly into the valley and nailed in the normal manner except that no nail is to be located closer than 150 mm (6") to the valley centreline and that two nails are to be located as shown at the end of each terminal strip.

Then apply the first course of shingles along the eaves of the intersecting roof area, extending it over previously applied shingles and parallel to the centre line of the valley. Cut and trim all points of valley shingles to prevent water from penetrating between the courses. Succeeding courses are applied and completed as indicated in Asphalt Shingles Construction Details.

1.2.6 Penetrations and Vertical Upstand Flashing

Vertical upstand flashings must be installed at all vertical intersections. When fasteners are required to secure exposed metal counter flashings only cladding screws, minimum No. 8 (18") with a rubber gasket grommet or washer, made of metal compatible and corresponding in colour to the metal flashing material are acceptable. Nails are not acceptable as exposed fasteners to secure exposed metal counter flashings.

Materials used must conform to Sheet Metal Material Standards in 1.1.2 above.

In addition, strip-in type roof penetration flashings (lead, aluminium, stainless streel, copper, etc.) must be properly sized to fitted roof pipe penetrations. Alternatively, when pipes are irregular in size, oversized flashings with sprayed foam insulation may be used.

Apron flashing shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") over the roof material and 100 mm (4") around the corners. On areas that need more than one length of flashing e.g. adjacent walls, only standing seams or ‘S’ locks can be used to join pieces.
Step flashing shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") between courses of roofing and have a 75 mm (3") headlap. Step flashing shall extend a minimum 75 mm (3") beyond the down slope corners and be folded, but not cut. Step flashing shall be placed flush with the butt edge (bottom) of each asphalt shingle course. Fastening shall be a nail placed 50 mm (2") down from the top edge and 25 mm (1") in from the outside edge on the deck flange portion of each step flashing.
Water diverter flashing shall be installed at all roof eaves to direct water away from walls and into drainage systems. Diverters shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") over roof material and be installed on a 20-degree angle to the vertical slope.
Backpan flashing shall extend a minimum 150 mm (6") up vertical surfaces, 450 mm (18") up the slope and 100 mm (4") beyond the corners. Corners must be folded, but not cut. If the upstand is more than 750 mm (30") wide, a saddle is recommended. In lieu of a saddle, a backpan that extends a minimum of one-sixth the width of the upstand but not less than 150 mm (6") vertically and up the roof slope to a point equal in height but not less than 450 mm (18") must be used.
Counter flashing must be used to shed water from vertical surfaces to the flashings.
Plastic vents or vent flashing shall have a minimum 75 mm (3") flange for the roof material on the upslope side and a minimum 50 mm (2") flange for the roof material on all other sides. Plastic vents or vent flashing shall not be used for combustion or grease laden venting. Acceptable plastic vents or vent flashing must conform to CSA-A93-M82 (R1992), or ICBO #4159.
Metal vents or vent flashing shall have a minimum 100 mm (4") flange for the roof material on all sides and a minimum vertical sealed height of 75 mm (3"). All seams must be fully soldered or welded. Material used must conform to Sheet Metal Material Standards detailed in 1.1.2 above.
Plumbing vent flashings shall have a minimum 100 mm (4") flange on all sides and be properly sized for the pipe. The flashing must allow for thermal movement of the vent pipe. Settle caps or storm collars must be used where possible. Acceptable plumbing vent flashings must conform to CSA B272-93.

1.2.7 Capping

Ridge capping must be acceptable for use and manufactured by the field asphalt shingle manufacturer. The ridge capping must be of the same material as the shingles and must be applied to provide a minimum double coverage. Capping must be installed in such a manner that nails are not exposed. Continuous proprietary ridge venting systems are also acceptable and are recommended for all areas with vaulted ceilings.

1.2.8 Guarantee

The work may qualify for a RoofStar 5-Year Roofing Guarantee or a RoofStar 10-Year Roofing Guarantee.

1.2.9 Ventilation - Attic Space / Cathedral / Insulated Roof Assemblies

The attic or ceiling space must be adequately ventilated according to appropriate Building Code standards. The design and selection of the ventilation system is the responsibility of the design authority.

Cathedral ceiling and / or insulated roof assemblies must have a minimum space for unobstructed air movement of 63 mm (2.5"), between the roof sheathing and the insulation where joist spaces are not individually vented, the spaces must be cross-strapped with purlins that are not less than 38 mm (1-1/2") x 38 mm (1-1/2") installed on top of the roof joists.

Note: Refer to the BC Building Code Part 9 for Housing and Small Buildings, Section 9.19 Roof Spaces, 9.19.1.3 Clearances.

Asphalt shingles applied over insulation and shingles applied to sheathing over insulation without the appropriate air space do not qualify for a RoofStar Guarantee.

1.2.10 Special Nailing Requirement

For slopes exceeding 1.75:1 (21" in 12") use 6 nails per shingle; 1 at each end and double nailed at each third point. Immediately upon installation, cement shingle tabs down with a spot of asphalt plastic cement approximately 22 mm in diameter, located at the centre of each tab. This may be exceeded by manufacturer’s requirements.

1.2.11 Wood Deck Overlay Sheathing (Non-Structural)

Non-Structural continuous sheathing overlay conversions installed over existing spaced sheathing (spaced strapping) and board (plank, mill, or shiplap) decks must conform to the following:

  • Overlay deck sheathing must conform to CSA 0151-04 Canadian Softwood Plywood, Grade C or better; or CSA 0121-M 1978 (R2003) Douglas Fir Plywood Grade C or better, minimum thickness 9.5 mm (3/8").
  • Direction of new sheathing may be either horizontal or vertical and joints are not required to be over supporting members, but are to be fully or intermittently supported by the strapping.
  • Spaces between strapping are to be filled in with additional strapping or new sheathing trimmed as necessary to provide edge support for the new overlay sheathing joints. Maximum allowable spacing of strapping is 200mm (8") between boards; all larger spaces are to be filled in with additional strapping.
  • Maximum nail spacing is to be 300 mm (12") o.c. fastened through existing strapping / boards into supporting members. Edges of new sheathing are to be nailed at a maximum of 150 mm (6") o.c. through strapping / boards and into supporting members as applicable. Nails for the new sheathing are to penetrate supporting members, (underlying trusses or rafters), a minimum of 19 mm (3/4").
  • End joints of new sheathing are to be staggered by a minimum of 400 mm (16") and spacing between sheathing is to be 2 mm (3/32") on all sides.
  • Metal drip edge flashing is to be installed at all eave and rake edges. Drip edge flashing is to extend to overlap existing fascia boards or wall cladding.
  • Clearance to all "hot" pipes must conform to the requirements set out in the BC Building Code (latest edition).

1.2.12 Photovoltaic Panel (PV) and Solar Water - Panel Mounting and Installation

  1. No PV or solar water panels may be mounted on shingled roofs having a pitch of less than 4:12.
  2. All PV or solar water panels designated for installation on a roof carrying a RoofStar Guarantee must display an authentic decal or plate indicating compliance with CSA Standard B272-93.
  3. Shingle underlayment requirements for STR-LS Asphalt Shingles shall apply to roof areas where PV or solar water panels are installed.
  4. All PV or solar water panels shall be mounted at least 150 mm (6 inches) from the finished roof surface (shingles).

2 Asphalt Shingle Application Specification: STR-LS (Low Slope)

LOW SLOPE APPLICATION: 1:6 (2" in 12") TO 1:3 (4" in 12")
This specification is intended to meet or exceed the requirements of the BC Building Code (latest edition).

2.1 MATERIALS

2.1.1 General

.1 Asphalt Shingles: manufactured to A123.1-05/A123.5-05 (R2010) for fibreglass felt shingles with a minimum mass of 34.3 kg (75.4 lb weight) per bundle. The shingle must be a single thickness strip type and approved for this construction by the manufacturer. (See Accepted Materials - Asphalt Shingles) Note: Interlocking or laminated style asphalt shingles are not acceptable for low-slope applications.
.2 Nails: large-head corrosion resistant roofing nails conforming to CSA B111; hot-dipped galvanized steel, aluminium, or stainless steel.
.3 Valley Materials: sheet metal to RoofStar Guarantee Standards (see above) or accepted modified bituminous membrane conforming to CGSB 37-GP-56M minimum thickness 3.5 mm at the selvage edge (see Accepted Materials - Eave Protection section of this Manual and appropriate building code requirements.
.4 Eave Protection: minimum 1 mm self-adhesive rubberised asphalt sheet material (See Accepted Materials - Eave Protection).
.5 Underlayment: minimum 1 mm self-adhesive, rubberised asphalt sheet material (see Accepted Materials - Underlayment).
.6 Water diverter Flashing: Minimum 0.56 mm (26 gauge) galvanized iron, 0.80 mm (0.032") aluminum, or 0.56 mm (0.0216", 16 oz) copper.
.7 Cladding Screws: Minimum No. 8 (⅛") with rubber gasket grommet or washer made of metal compatible and corresponding in colour to metal flashing material.

2.1.2 Sheet Metal (Flashing)

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").

2.2 APPLICATION

2.2.1 Deck Requirements

[Minimum slope 1:6 (2" in 12")]
.1 New wood decks and existing decks when re-roofing shall be constructed of plywood or OSB securely fastened to supports. Shiplap and dimensional lumber are not acceptable deck materials for this assembly.
.2 Plywood or non-veneer panels for roof decks shall conform, as a minimum, to the requirements of the Building Code; but we strongly recommend, for better nailing and less deflection, that the following be used: plywood; 12.7 mm (½") thick when supported at 400 mm (16") o/c or 15.9 mm (58") thick when supported at 600 mm (24") o/c (refer to RoofStar Guarantee Standards in Roof Decks).
.3 Wood decks constructed of shiplap and dimensional lumber shall be overlain with sheathing that conforms to CSA 0151-04, Canadian Softwood Plywood, Grade C or better; or CSA 0121-M 1978 (R2003) Douglas Fir Plywood, Grade C or better. Minimum thickness to be 9.5 mm (38"). Refer to 2.1.9 Wood deck overlay sheathing (Non-Structural) for sheathing overlay installation requirements.
.4 When plywood or non-veneer (OSB or wafer) panels fastened to metal Z-bars (girts) are used for roof sheathing (decking), sheathing must be a minimum thickness of 15.9 mm (5/8"). In addition, asphalt shingle roofing nails must not penetrate the roof sheathing when metal Z-bars (girts) are used as the attachment substrate for roof deck sheathing.
Note: For re-roofing over old deck, deck must comply to specifications as for new work. (refer to RoofStar Guarantee Standards for Wood Deck).

2.2.2 Tie-in (Re-roofing or Building Additions)

Where a new roof is tied-in to an existing roof, the two areas must be isolated and separated by a curb joint properly constructed a minimum height of 125 mm (5”), attached to the structure and properly flashed.

2.2.3 Eave Protection and Underlay

.1 Provide an underlayment of self-adhesive rubberized asphalt sheet over the entire deck, layered horizontally to the roof slope with a minimum headlap of 50 mm (2"), end lap 150 mm (6") (see Eave Protection & Underlayment).
Underlay must be stripped in to all adjacent vertical surfaces, curbs, and penetration flashings. Stripping must be carried a minimum of 125 mm (5") up vertical surfaces and overlap a minimum 150 mm (6") onto the field areas.

2.2.4 Shingles: Field Application

.1 Starter strip shall be shingles applied to the manufacturer’s printed instructions
.2 First course shall be applied with tabs overhanging fascia board sufficiently to lead water into eaves trough (normally 37 mm [1-1/2"]). Each shingle shall be applied with a minimum of four nails.
.3 Each succeeding course shall be applied in a like manner with all vertical and horizontal lines running true, or a random pattern as per the manufacturer’s printed instructions. Exposure and nailing pattern must conform to the manufacturer’s printed instructions.
.4 Shingles must be sealed in a bed of compatible mastic at all gable edges and valleys.

2.2.5 Valleys

Only Open Valleys are permitted for low-slope asphalt shingle roofing systems

.1 Metal valleys shall be flashed with not less than 600 mm (24") wide sheet metal. Edges of metal valleys must be fastened to the deck at 200 mm (8") o.c. and tied in to the underlay with a minimum 200mm (8") strip of self-adhered modified bitumen underlay material.
.2 Membrane valleys must be not less than 1 metre (39.4") wide and a minimum 150 g / sq. m polyester or equal strength polyester-fibreglass reinforced granulated modified bitumen membrane roofing material with a minimum thickness of 3.5 mm at the selvage edge. Materials must be installed to the manufacturer’s printed instructions.
.3 Cut and trim all points of valley shingles.'

2.2.6 Capping

Ridge and hip capping must be acceptable for use by the asphalt shingle manufacturer and must be of the same material as the shingles and must be applied to provide double coverage. Capping must be nailed in such a manner that nails are not exposed except for the last cap, where exposed nails must be gummed.

2.2.7 Penetrations and Vertical Upstand Flashing

Materials used must conform to Sheet Metal Material Standards in 3.1.2 above.

In addition, strip-in type roof penetration flashings (lead, aluminium, stainless streel, copper, etc.) must be properly sized to fitted roof pipe penetrations. Alternatively, when pipes are irregular in size, oversized flashings with sprayed foam insulation may be used.

Vertical Upstand Flashing: must be installed at all vertical intersections. When fasteners are required to secure exposed metal counter flashings only cladding screws, minimum No. 8 (⅛") with a rubber gasket grommet or washer, made of metal compatible and corresponding in colour to the metal flashing material are acceptable. Nails are not acceptable as exposed fasteners to secure exposed metal counter flashing.
Apron flashing: shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") over the roof material and 100 mm (4") around the corners. On areas that need more than one length of flashing e.g. adjacent walls, only standing seams or 'S' locks can be used to join pieces.
Step flashing: shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") between courses of roofing and have a 75 mm (3") head-lap. Step flashing shall extend a minimum 75 mm (3") beyond the down slope corners and be folded, but not cut. Step flashing shall be placed flush with the butt edge (bottom) of each asphalt shingle course. Fastening shall be a nail placed 50 mm (2") down from the top edge and 25 mm (1") in from the outside edge on the deck flange portion of each step flashing.
Water diverter flashing shall be installed at all roof eaves to direct water away from walls and into drainage systems. Diverters shall extend a minimum 125 mm (5") up vertical surfaces, 100 mm (4") over roof material and be installed on a 20-degree angle to the vertical slope.
Backpan flashing: shall extend a minimum 150 mm (6") up vertical surfaces, 450 mm (18") up the slope and 100 mm (4") beyond the corners. Corners must be folded, but not cut. If the upstand is more than 750 mm (30") wide, a saddle is recommended. In lieu of a saddle, a backpan that extends a minimum of one-sixth the width of the upstand but not less than 150 mm (6") vertically and up the roof slope to a point equal in height but not less than 450 mm (18") must be used. The leading edge of the flashing must be stripped in to the underlay.
Counter flashing: must be used to shed water from vertical surfaces to the flashing.
Metal vents: or vent flashing shall have a minimum 100 mm (4") flange for the roof material on all sides and a minimum vertical sealed height of 200mm (8") on all roof slopes of less than 1:3 (4" in 12"). All seams must be fully soldered or welded. Material used must conform to the Sheet Metal standards in this Manual (again, refer to 3.1.2 above). Flanges and succeeding courses of shingles must be set in a trowel coating of compatible mastic. The leading edge of the flashing must be stripped in to the underlay.
Plumbing vent flashings: shall have a minimum 100 mm (4") flange on all sides and be properly sized for the pipe. The flashing must allow for thermal movement of the vent pipe. Settle caps or storm collars must be used where possible. Acceptable plumbing vent flashings must conform to CSA B272-93. Flanges and succeeding courses of shingles must be set in a trowel coating of compatible mastic. The leading edge of the flashing must be stripped in to the underlay.

2.2.8 Guarantee

The work may qualify for a RoofStar 5-Year Roofing Guarantee or a RoofStar 10-Year Roofing Guarantee

2.2.9 Ventilation – Attic Space / Cathedral / Insulated Roof Assemblies

The attic or ceiling space must be adequately ventilated according to appropriate Building Code standards. The design and selection of the ventilation system is the responsibility of the design authority.

Cathedral ceiling and / or insulated roof assemblies must have a minimum space for unobstructed air movement of 63 mm (2.5"), between the roof sheathing and the insulation where joist spaces are not individually vented, the spaces must be cross-strapped with purlins that are not less that 38 mm (1½") x 38 mm (1½") installed on top of the roof joists.

Note: Refer to the BC Building Code Part 9 for Housing and Small Buildings, Section 9.19 Roof Spaces, 9.19.1.3 Clearances.

Asphalt shingles applied over insulation and shingles applied to sheathing over insulation without the appropriate air space do not qualify for a RoofStar Guarantee.

2.2.10 Wood Deck Overlay Sheathing (Non-Structural)

Non-Structural continuous sheathing overlay conversions installed over existing spaced sheathing (spaced strapping) and board (plank, mill, or shiplap) decks must conform to the following:

  • Overlay deck sheathing must conform to CSA 0151-04 Canadian Softwood Plywood, Grade C or better; or CSA 0121-M 1978 (R2003) Douglas Fir Plywood Grade C or better, minimum thickness 9.5mm (38").
  • Direction of new sheathing may be either horizontal or vertical and joints are not required to be over supporting members, but are to be fully or intermittently supported by the strapping.
  • Spaces between strapping are to be filled in with additional strapping or new sheathing trimmed as necessary to provide edge support for the new overlay sheathing joints. Maximum allowable spacing of strapping is 200mm (8") between boards; all larger spaces are to be filled in with additional strapping.
  • Maximum nail spacing is to be 300 mm (12") o/c fastened through existing strapping/boards into supporting members. Edges of new sheathing are to be nailed at a maximum of 150 mm (6") o/c through strapping/boards and into supporting members as applicable. Nails for the new sheathing are to penetrate supporting members, (underlying trusses or rafters), a minimum of 19 mm (¾").
  • End joints of new sheathing are to be staggered by a minimum of 400 mm (16") and spacing of sheathing is to be 2 mm (3/32") on all sides.
  • Metal drip edge flashing is to be installed at all eave and rake edges. Drip edge flashing is to extend to overlap existing fascia boards or wall cladding.
  • Clearance to all "hot" pipes must conform to the requirements set out in the BC Building Code (latest edition).


Asphalt Shingle Roof Systems

Accepted Materials

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