SS Section 2: Asphalt Shingle Roofing

1. Sheet metal flashing shall consist of not less than:
   

   *REVISED 2017-10

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.

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.

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.

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

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.

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

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.

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.

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.