What is the typical size of step flashings used in wood shingle/shake systems?

The size of step flashings used in wood shingle or shake roofing systems is generally 8 inches wide and 3 inches long. This size is designed to provide adequate coverage and support for the shingles while effectively directing water away from the seams where the roof plane meets walls or other vertical structures.

The width of the flashing (8 inches) ensures that it overlaps sufficiently with both the shingles and the structure it is protecting, preventing water infiltration. The length (3 inches) allows it to extend adequately onto the shingles below, facilitating effective water diversion. This size is commonly accepted in roofing practices and aligns with industry standards, ensuring both structural integrity and longevity of the roofing system.

The other options, while they may seem plausible, do not provide the same level of coverage or protection, which can lead to potential leaks and damage over time.