(1) Except as otherwise permitted in Sentence (5), chimney saddles shall be installed where the upper side of a chimney on a sloping roof is more than 750 mm wide.
(2) Chimney saddles shall be covered with sheet metal or roofing material of weight and quality equivalent to the roofing.
(3) Saddles shall be flashed where they intersect the roof.
(4) The intersection of the saddle and the chimney shall be flashed and counterflashed as required in Article 18.104.22.168.
(5) A chimney saddle need not be installed if the intersection between the chimney and roof is protected by sheet metal flashing that extends up the chimney to a height equal to at least one-sixth the width of the chimney, but not less than 150 mm, and up the roof slope to a point equal in height to the flashing on the chimney, but not less than 1.5 times the shingle exposure.
(6) Flashing described in Sentence (5) at the chimney shall be counterflashed as required by Article 22.214.171.124.
Article 126.96.36.199. Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.
A saddle or “cricket” should be installed when the upper side of a chimney is more than 750 mm (30 in,) wide. These are constructed out of wood during the roof framing operations and are usually covered with sheet metal (Figure 126). The saddle should be suitably flashed at the roof and at the chimney.
A saddle is not required if the metal flashing is carried up both the roof and the chimney to a height at least equal to one-sixth the chimney width. On roof slopes behind a chimney, the flashing should extend up the roof and up the chimney to a point equal in height to the chimney counter flashing, but not less than 150 mm (6 in.) or 11⁄2 times the shingle exposure. Open joints or laps should be soldered or sealed, or a locked joint used.
Source : Canada Mortgage and Housing Corporation (CMHC)