Starter Strip Asphalt Shingles on Slopes of Less Than 1 in 3
(1) A starter strip shall be installed as in Article 9.26.7.2.
(2) Starter strips required in Sentence (1) shall be laid in a continuous band of cement not less than 200 mm wide.
Article 9.26.8.2. Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.
Asphalt Shingles on Low Slopes of 1:6 to 1:3
Care is required to ensure that the roof covering on a low slope roof is waterproof. Except for the first two courses, use three thicknesses of shingles on the entire roof including hips and ridges. Maintain a shingle exposure of not more than one-third the full height of the shingle. Install starter strips as for higher sloped roofs, but apply them over a continuous band of cement not less than 200 mm (8 in.) wide. The first course of shingles is then cemented to the strip with a continuous band of cement that is 100 mm (4 in.) wider than the shingle exposure. For example, a 250 mm (10 in.) band of cement should be used when the shingle exposure is 150 mm (6 in.). The succeeding courses of shingles are laid on a band of cement 50 mm (2 in.) wider than the shingle exposure, so that a 200 mm (8 in.) band is used when the exposure is 150 mm (6 in.).
To avoid defacing the exposed surface of the shingles with cement, the band should be located between 25 and 50 mm (1 and 2 in.) above the butt edge of each succeeding course of shingles. Staple or nail each shingle strip in place with four fasteners located above the exposed portion of the shingle. If cold application cement is used, it should be applied at a rate of approximately 0.5 L/m2 (1 gal./100 sq. ft.) of
cemented area. Hot-application cement is applied at a rate of approximately 1 kg/m2 (0.2 lb./sq. ft.) of cemented area. This technique is necessary only for slopes lower than 1:4 since there are special low slope shingles of sufficient length to maintain the three thicknesses necessary at roof pitches of 1:4 or greater.
Source : Canada Mortgage and Housing Corporation (CMHC)
Note : Starter strips are a key component of your new roofing system. It is used on the lower edge of the roof and along the rake edges of the roof. When heated, the tar on starter strips bonds to the shingle it is meant to seal. This helps protect your home from various weather events, such as high winds, hail, and heavy rain.
