Which term describes a half-conical opening formed at a cut edge of shingles?

The term "fishmouth" accurately describes a half-conical opening that can occur at the cut edge of shingles. This opening is typically the result of improper installation techniques or due to the natural contraction and expansion of roofing materials. A fishmouth is problematic because it can allow water to penetrate under the shingles, leading to potential leaks and further damage to the roofing structure.

Understanding this term is crucial in roofing, as it highlights a common issue that roofers and homeowners should be aware of. Identifying a fishmouth allows for timely repairs, which can extend the life of the roof and maintain its integrity.

In contrast, a flange refers to a projecting flat rim or edge, typically used in relation to roofing components but does not specifically describe an opening at the edge of shingles. Flashing is a material used to direct water away from joints and openings in the roofing structure, and while it plays a vital role in preventing water intrusion, it does not pertain to the shape or formation of shingles. A face nail, meanwhile, refers to a nail that is driven through the surface of a roofing material for securing it, but it does not relate to the formation of a conical opening.