Inadvertent Mechanical Damage

Inadvertent mechanical damage is commonly found on asphalt shingles.  Human activities on asphalt shingle roofs, particularly during warm weather, can mar or otherwise damage shingles.  Examples of this include: shingle installers dropping or dragging materials or tools across the roof; installers cutting through a shingle and affecting the shingle below (see the photograph below); and foot scuffing along the bottom exposed edge of an installed shingle.  Mechanical damage occurs more easily when the shingles are warm because the asphalt in the shingles is softer at higher temperatures. However, it can also occur in winter months, particularly from snow removal activies.