What is a common defect found in roofing systems?

Missing or damaged shingles is a common defect found in roofing systems because shingles serve as the primary barrier against water intrusion and environmental factors. When shingles are missing, cracked, or otherwise damaged, it compromises the integrity of the roof, which can lead to leaks and further structural problems. Over time, exposure to harsh weather conditions, such as heavy rain, wind, and UV light, can cause shingles to deteriorate, curl, or become dislodged, making it essential to regularly inspect and maintain roof shingles to ensure the longevity and functionality of the roofing system.

The other options, while they represent issues that can affect a property, are not directly related to roofing systems. Clogged gutters can lead to water backup but do not constitute a defect in the roof itself. A cracked foundation pertains to structural issues primarily at the base of a building, and broken windows relate to issues with the glazing or frames rather than the roof. Thus, the focus on missing or damaged shingles as the correct answer highlights its direct relevance to roofing system defects.