In wet climates like Vancouver, moss growth is a significant concern because persistent rain and humidity keep roofs damp, which allows moss spores to germinate rapidly on shingles. When left untreated, moss traps moisture against the roof surface, leading to several types of damage:

• It accelerates granule loss and causes shingles to curl.
• It can lead to water penetration, potentially damaging roof decking and attics.
• Moss buildup in valleys and gutters can create ice dams and cause water backup.
• The trapped moisture promotes rot, which compromises the integrity and lifespan of the roofing system.

To manage these issues, professionals recommend tailored maintenance, such as manual moss removal without pressure washing and the application of eco-friendly treatments. Regular inspections are necessary to monitor moss density, especially in shaded areas or on north-facing slopes where moisture is most likely to persist.