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SS Section 2: Asphalt Shingle Roofing

SS-2.1 Decks

SS-2.1.1 General

  1. Asphalt shingle application directly over rigid insulation is not permitted.
  2. Asphalt shingle application directly over dimensional lumber is not permitted.
  3. Asphalt shingles must be applied to wood sheathing over a ventilated air space.
    *ADDED 2013-04
  4. For new construction, the roof decking shall be minimum 11.1mm (7/16”) thick O.S.B. or minimum 12.7mm (1/2”) thick plywood sheathing.
  5. When reroofing, plywood or O.S.B. roof sheathing shall be minimum 9.5mm (3/8”) thick.
  6. An upper asphalt shingled roof area shall not drain directly on a lower asphalt shingled roof area. Drainage shall be diverted using downspouts, diverters and/or gutters.
    *ADDED 2020-04

SS-2.1.2 Strength

  1. The roof framing and decking shall be designed of sufficient strength so that they will support the anticipated load such as construction loads. Roof decks shall be free of damaged, deteriorated or decayed wood.

SS-2.1.3 Surface

  1. The surface of all roof decks to which a roofing system is to be applied shall be sufficiently clean and dry so that proper attachment can take place.
  2. Roofing over existing asphalt shingles is not permitted, tear off old materials to expose the decking.
  3. Repair damaged or deteriorated decking and fill abandoned deck openings with similar materials prior to reroofing.

SS-2.1.4 Slope

  1. The minimum roof slope permitted for issuance of an asphalt shingle roofing Warranty Certificate is 4:12 (1:3).
  2. Use a membrane roofing system for roof slopes less than 4:12 (1:3).

SS-2.2 Roofing Materials

SS-2.2.1 General

  1. The roofing materials shall conform to the National Building Code — Alberta Edition and shall comply with their applicable materials standard.
    *REVISED 2020-04
  2. Materials shall be adequately labeled so that proper identification of the materials may be made.

SS-2.2.2 Protection and Storage

  1. All roofing materials that can be adversely affected by moisture shall be protected prior to application and only dry materials shall be applied.
  2. Rolls of felt are to be stored on end, covered and out of danger of water penetration.

SS-2.2.3 Application Limitations

  1. No roofing material is to be applied when the weather or the condition of its substrate is such that the required installation procedures could not be followed or which would jeopardize the performance of the roofing system or the safety of the applicators.

SS-2.2.4 Asphalt Shingles

  1. Inorganic asphalt shingles shall conform to CSA A123.5-16, “Asphalt Shingles made from glass felt and surfaced with mineral granules”. Shingles may be three-tab or laminate.
    *REVISED 2020-04

SS-2.2.5 Organic Felt

  1. The organic felt used for the underlayment and eave protection shall be No.15 asphalt saturated non-perforated felt conforming to CSA A 123.3-05 (R2015), “Asphalt Saturated Organic Roofing Felt”.
    *REVISED 2020-04

SS-2.2.6 Nails

  1. Nails used for roofing shall be corrosion-resistant roofing or shingle nails conforming to ASTM F1667-18(a) “Driven Fasteners: Nails, Spikes and Staples”
    *REVISED 2020-04
  2. Nails shall have sufficient length to penetrate through the asphalt shingle roofing and roof sheathing or have a minimum penetration of 25mm (1″) into the roof decking.
  3. Nails shall have a head diameter of not less than 9.5mm (3/8″) and a shank thickness of not less than 2.95mm.

SS-2.2.7 Staples

  1. The use of staples for the attachment of asphalt shingles is not permitted.

SS-2.3 Flashing at Intersections

SS-2.3.1 Materials

  1. Sheet metal flashing shall consist of not less than:
    *REVISED 2017-10
    • 15 kg/m² (3 P.S.F.) thick sheet lead,
    • 0.41mm (30 ga.) thick Z275 galvanized steel,
    • 0.56mm (16 oz.) thick copper,
    • 0.60mm (22 ga.) thick aluminum
    • or approved alternates.

SS-2.3.2 Valley Flashing

  1. Open, woven or closed cut valleys are permitted for W.C. issuance. California style valleys are not permitted.
    *REVISED 2010-06
  2. Open valleys must be employed for laminated asphalt shingle applications.
    *REVISED 2016-04
  3. Where sloping surfaces of shingle roofs intersect to form a valley, the valley shall be flashed with a minimum of one (1) ply of 914mm (36”) wide self adhering modified bituminous membrane centered in valley.
  4. Open valleys shall be flashed with an additional layer of sheet metal not less than 600 mm (2 ft.) wide. Where adjoining roof areas differ in pitch, the metal valley flashing shall contain a 25 mm (1”) high centre crimp.
  5. The shingle underlayment shall be carried over (on top of) the edges of the sheet metal valley flashing and be trimmed to a line parallel to the interior cut edge of the shingle’s triangular clip. Shingles and shingle segments on both sides of valleys shall have their top valley edge clipped to form an approximately 50mm (2”) wide triangle to direct runoff towards the valley’s centerline.
  6. For woven and closed cut valleys, shingles shall be tightly pressed into the valley and fastened no closer than 150mm (6″) from the valley centre line. Shingle terminations on opposite sides of the valley shall be fastened with a minimum of two (2) roofing nails placed vertically above one another.
  7. For closed cut valleys, trim the overlapping shingles at a minimum distance of 50mm (2″) up/back from the valley centerline.

SS-2.3.3 Intersection of Shingle Roofs and Walls

  1. The intersection of shingle roofs and walls or chimneys shall be protected with flashing in accordance with the National Building Code — Alberta Edition.
    *REVISED 2020-04
  2. Sheet metal step flashing shall be installed when the rake of a roof abuts a vertical wall or projection.

SS-2.3.4 Chimney Saddles

  1. For sloping roofs, chimney saddles shall be installed where the upslope side of a chimney is more than 750mm (29.5″) wide. See the National Building Code — Alberta Edition for details.
    *REVISED 2020-04
  2. For chimneys less than 750mm (29.5″) wide, a chimney saddle need not be installed if the intersection between the chimney and roof decking is protected by one (1) ply of self-adhering modified bituminous membrane covered by a sheet metal flashing (back pan) that extends up the chimney to a height equal to not less than one sixth the width of the chimney, but no less than 150mm (6″) in height and shall extend up the roof slope to a point equal in height to the top edge of the chimney flashing, but not less than 1.5 times the shingle exposure.
    *REVISED 2020-04
  3. Chimney saddles and valleys shall be treated in accordance with Clause 2.3.2.

SS-2.4 Eave Protection and Metal Flashing

SS-2.4.1 Eave Protection

  1. Eave protection shall extend from the roof edge a minimum distance of 900mm (3 ft.) up the roof slope to a line not less than 300mm (1 ft.) inside the inner face of the exterior wall.
  2. Eave protection is not required:
    • Over unheated garages, carports and porches,
    • Where the roof overhang exceeds 900mm (3 ft.) measured along the roof slope from the edge of the roof to the inner face of the exterior wall,
    • On roofs with slopes of 8:12 (1:1.5) or greater.

SS-2.4.2 Materials

  1. Eave protection shall be laid beneath the starter strip shall consist of one of the following:
    *REVISED 2020-04
    • No. 15 asphalt saturated felt conforming to CSA A123.3-05, laid in two plies lapped 480mm (19″) and cemented together with lap cement,
    • Type M (mineral-surfaced roll roofing) or Type S (smooth-surfaced roll roofing) conforming to CSA A123.2-03, laid with not less than 100mm (4″) head and end laps cemented together with lap cement. This application is restricted to warm weather applications to minimize the possibility of wrinkling,
    • Glass fibre or polyester fibre coated base sheets, or
    • Self-sealing composite membranes consisting of modified bituminous coated material.

SS-2.4.3 Drip Edge Flashing

  1. Pre-finished or galvanized sheet metal drip edge flashing shall be installed along roof eaves and rakes. The vertical flange shall be spaced a minimum distance of 6.4mm (1/4”) from the fascia face. The deck flange shall extend a minimum distance of 75mm (3”) on to the roof decking and shall be nailed at maximum 400mm (16”) centres prior to shingle application.
    *REVISED 2010-06
  2. At the eaves, the sheet metal drip edge flashing shall be fastened directly to the roof decking beneath the eave protection.
  3. At roof rake edges, the drip edge shall be fastened to the roof decking over the underlayment and eave protection membranes.
  4. Exposed flashing edges shall be hemmed.

SS-2.5 Underlayment

SS-2.5.1 Materials

The field of the decking shall be completely covered with a minimum of;

    • Asphalt-saturated sheathing paper weighing not less than 0.195 kg/m²,
    • No. 15 plain or perforated asphalt-saturated felt, or
    • Synthetic underlayment
      *REVISED 2020-04

SS-2.5.2 Installation

  1. Underlay shall be installed parallel to the eaves with head and end lap of not less than 100mm (4″).
  2. The underlay shall overlap the eave protection a minimum distance of 100mm (4”).
  3. The top edge of each underlayment strip shall be sufficiently fastened to hold the underlayment in place until the shingles are applied.
  4. Ensure the underlayment is lying flat prior to shingle application.

SS-2.6 Ventilation

  1. Every roof space or attic above an insulated ceiling shall be ventilated with openings to the exterior to provide an unobstructed vent area of not less than 1/300 of the insulated ceiling area. Vents may be roof type, eave type, soffit type, gable-end type or any combination thereof, and shall be uniformly distributed on opposite sides of the building. Roof vents shall be equally distributed so that approximately 50 percent of the required vent area is located near the lower part of the roof and approximately 50 percent of the required vent area is near the ridge. For exceptions see National Building Code — Alberta Edition, Section 9.19.1, Venting.
    *REVISED 2020-04

SS-2.7 Application

SS-2.7.1 Coverage

Coverage shall be not less than two (2) thicknesses of asphalt shingles over the entire field of the roof, disregarding three tab shingle cutouts.

SS-2.7.2 Starter Strip

A starter strip shall be installed along the lower edge of the roof so that it extends approximately 19.0mm (3/4”) beyond the eaves and rakes of the roof and be fastened along the bottom edge with nails spaced not more than 300mm (1 ft.) on centre.
Starter strips shall be;
    • At least Type M (mineral-surfaced roll roofing) not less than 300 mm wide,
    • Shingles of the same weight and quality as those used as a roof covering with tabs facing up the roof slope, or
    • Pre-manufactured starter strips installed with sealant at the eaves.
      *REVISED 2020-04

SS-2.7.3 Head Lap

  1. Shingles shall have a head lap of not less than 50mm (2”).

SS-2.7.4 Fasteners

  1. Shingles shall be fastened with no fewer than four (4) roofing nails per shingle, placed in the nailing zone so that nails penetrate through both shingle courses and the roof decking, with no exposed nails. Nails shall be driven flush with the shingle surface.
    *REVISED 2010-06
  2. For roof pitches greater than 12:12, asphalt shingles shall be fastened with a minimum of six (6) roofing nails per shingle.
  3. Fasteners shall be located 25mm (1”) to 38mm (1-1/2”) from the end of each shingle and the remaining fasteners equally spaced between them.
  4. For three tab shingles, roofing nails shall be located not less than 12.7mm (1/2”) above the tops of the cutouts.
  5. Fastener quantities may be reduced for trimmed shingles in proportion to the shingle segment’s width. No fewer than two (2) roofing nails shall be used to secure trimmed shingle segments.
    *REVISED 2016-04
  6. No nail head shall be left exposed to the weather.

SS-2.7.5 Securing of Tabs

  1. Shingles and shingle tabs shall be secured by a self sealing adhesive strip or by additional application of plastic cement when hand tabbing.
    *REVISED 2015-03
  2. Follow shingle manufacturer’s application recommendations and allow one (1) season for shingles to seal. Shingles shall be hand tabbed during cold weather applications in accordance with manufacturers recommendations.
    *REVISED 2016-12
  3. The first course of shingles shall be hand tabbed to the starter shingles along eave and rake edges.
  4. Partial and trimmed shingles shall be hand tabbed at terminations such as gable edges, rakes, valleys, vents, curbs, etc.

SS-2.7.6 Hips and Ridges

  1. Hip and ridge shingles must be applied so they extend not less than 100mm (4”) on either side of the hip or ridge centre line and shall be lapped not less than 150mm (6”). Shingle laps shall face away from the prevailing wind direction.
  2. Shingles must be fastened with nails located not more than 25mm (1”) from the edge and 25mm (1”) above the butt of the overlying shingle on both sides of the hip or ridge centre line.

SS-2.8 Accepted Asphalt Shingles

SS-2.8.1 Inorganic Asphalt Shingles

  1. Three tab and architectural inorganic asphalt shingles complying with C.S.A. A123.5-16, “Asphalt Shingles Made from Glass Felt and Surfaced with Mineral Granules” and successfully completing an ARCA Warranty Ltd. material evaluation as accepted products.

Building Products of Canada (BP)

  • Mystique 42
  • Vanguard 42 IR


  • IKO Cambridge
  • IKO Dynasty
  • IKO Nordic

Malarkey Roofing Products

  • Highlander CS Laminate
  • Legacy SBS Laminate

Owens Corning

  • TruDefinition® Duration® Shingles with SureNail® Technology
  • TruDefinition® Duration® Storm Shingles with Sure Nail® Technology
  • Oakridge® shingle