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We must take into consideration that several rows of slates are going to butt against the side of the chimney column. Since the slates overlap each other, the side flashing on the chimney must be cut into sections that overlap each other as well, otherwise one long piece of side flashing would allow water to run under the edge of the slates.
The side flashing pieces need not be installed as separate step and counter flashings, but can be installed as single pieces. This single side-piece system works well when re-flashing smaller chimneys, especially on older buildings that have already settled. Very large brick or stone chimneys may be easier to flash using separate step and counter flashings. Chimneys on new construction installed by Toronto roofers also benefit from a combination of step and counter flashing as the roofs will settle slightly over time while the chimney will not. This causes the step flashing, attached to the roof, to drop in relation to the counter flashing, attached to the chimney, which is not a problem if the two flashings are separate.