Roof cracks are primarily caused by weathering, structural stress, and material degradation. Common triggers include prolonged exposure to heavy rain, wind, ice, and temperature fluctuations. Foot traffic, improper installation, and aging materials further contribute to cracking. Stress from uneven settling or weak fasteners can also create weak points in the roof structure.

Weathering is the leading cause of roof cracks, with extreme weather accelerating material breakdown. For instance, repeated freeze-thaw cycles weaken asphalt shingles and concrete tiles, leading to brittleness and cracking. A 2021 study by the National Roofing Contractors Association (NRCA) found that 68% of roof failures in cold climates involved cracking due to thermal expansion and contraction. Similarly, wind speeds exceeding 50 mph can lift and stress roof edges, causing splits in vulnerable areas. Material degradation is another critical factor; older roofs (over 20 years) are 4.2 times more likely to crack than newer ones, per a 2020 report by the U.S. Department of Housing and Urban Development (HUD). This is due to UV radiation degrading synthetic materials and asphalt, while concrete tiles lose tensile strength by 15% every decade. Foot traffic, though less common, accounts for 12% of cracks in commercial buildings, as reported by the International Association of Roofing contractors (IARC). Improper installation exacerbates risks; 23% of roofs with mismatched flashing or poorly secured layers develop cracks within five years, according to the NRCA. These factors collectively highlight the importance of regular inspections, durable materials, and professional installation to mitigate cracking risks.