What is an important factor in moss growth on roofs?

In the context of moss growth on roofs, improper drainage and moisture retention play a crucial role. Moss thrives in environments that are consistently damp, so when water is not effectively drained from a roof, it creates the ideal conditions for moss spores to settle and grow. Roofs with structural issues that allow water to pool or areas that do not dry out quickly enough due to shade or poor airflow can be particularly prone to moss growth.

While the age of the roofing material, roof design, and external temperature fluctuations can influence the conditions on a roof, it is primarily the moisture retention and drainage that provide the essential environment for moss to flourish. For instance, a roof that retains water due to structural design flaws can keep the surface wet long enough to support moss, whereas a well-draining roof system can help reduce moisture and inhibit growth. Thus, addressing drainage issues is vital for preventing moss infestation on roofing materials.