What happens to shingles as they absorb moisture and subsequently dry?

Shingles undergo a specific physical response to moisture absorption and drying, which is critical for their durability and effectiveness as roofing materials. When shingles absorb moisture, they expand due to the increase in volume as the material takes on water. This expansion can lead to increased stress on the shingle and underlying roofing components.

As the shingles dry, they contract as the moisture evaporates. This cycle of expanding and contracting can impact the integrity of the roofing system over time. The continuous movement can lead to loosening of shingles, and ultimately might cause them to become more vulnerable to damage, such as cracking or curling.

Understanding this process is essential for home inspectors as it helps assess the condition of shingles in relation to moisture problems, and can be a significant factor in overall roof health. Proper installation and maintenance can mitigate these effects, extending the lifespan of the roofing materials.