The mountains change the weather, not just the view
Weather systems moving in off the water get pushed upward as they hit the North Shore mountains, and that lift wrings more precipitation out of them than falls on flatter areas further from the mountains. The practical result for a roof is more total rainfall, more days of the year with at least some rain, and less time between storms for a roof to actually dry out.
A roof that dries fully between rain events ages very differently from one that stays damp for most of the wet season. Constant moisture is what feeds moss growth, softens organic debris into a moisture holding mat, and keeps the roof deck itself closer to saturation than a drier climate's roof ever experiences.
Tree canopy compounds the effect
A large share of North Shore properties, particularly in Lynn Valley, Edgemont, and the upper streets of West Vancouver, sit under mature cedar and fir canopy. That canopy shades the roof for a large part of the day, which slows drying even further after a storm has passed. The combination of high rainfall and heavy shade is close to the ideal condition for moss, and it is a large part of why moss removal is one of the most common services we provide across the North Shore rather than an occasional add-on.
What this means for material choice
This climate rewards roofing decisions that account for sustained moisture rather than occasional rain. Underlayment that runs further up valleys and eaves than the bare code minimum, ventilation that actually moves air through the attic space so the deck can dry from underneath, and gutter systems sized for real rainfall volumes rather than a general standard all matter more here than in a drier part of the region.
Material choice matters too. Cedar can perform well here, but only on lots with enough sun exposure and airflow to let it dry between storms. On heavily shaded lots, a material with less sensitivity to sustained moisture often gives more consistent long term results.
What actually slows the wear down
Regular cleaning to remove moss and debris before it becomes established, proper attic ventilation, gutters sized and maintained for the volume they actually need to carry, and prompt attention to individual damaged shingles rather than waiting for a section to fail: none of these are exotic fixes, and none of them stop a North Shore roof from working harder than a roof somewhere drier. They do meaningfully extend how long that roof lasts before it needs major work.