The Best Metal Roof for the Pacific Northwest
Quick answer
In the wet, mild Pacific Northwest, the enemies are constant rain, moss, and damp — and aluminum metal roofing beats them. It cannot rust or rot, its smooth interlocking surface resists moss and algae far better than shingles or cedar, and it sheds the region's heavy rainfall while needing almost no maintenance. Interlock is manufactured in the region (Delta, BC) for exactly these conditions.
The Pacific Northwest roofing problem
The Northwest's climate is mild but relentlessly wet: months of rain, high humidity, and heavy shade create the perfect environment for moss, algae, and rot. Cedar shakes rot and grow moss; asphalt shingles trap moisture and host algae streaks; and any iron-based metal fights corrosion in the damp. Roofs here don't usually fail from a single storm — they degrade slowly from constant moisture and biological growth.
Why aluminum wins in the wet
Aluminum is almost purpose-built for the Northwest. It cannot rust and cannot rot, so constant rain and damp don't degrade it. Its hard, smooth, interlocking surface gives moss and algae little to grip, so it stays cleaner than rough shingles or organic cedar, and it sheds heavy rainfall efficiently with no absorption. The result is a roof that keeps looking and performing well through year after year of Northwest wet — with only the occasional rinse.
Low maintenance and local roots
For a region where cedar and shingle roofs demand cleaning, treating, and moss control, aluminum's near-zero maintenance is a real quality-of-life upgrade — no annual moss-killing, no re-treating, no premature replacement. And it's local knowledge: Interlock is manufactured in Delta, British Columbia, in the heart of the coastal Northwest, with decades of roofs proving out in precisely this rain-and-damp climate. Choose a profile for your home's style; performance is the same across all of them.
Frequently Asked Questions
What is the best roof for a rainy climate?
Aluminum metal roofing. It cannot rust or rot in constant rain and damp, resists the moss and algae that plague shingles and cedar, sheds heavy rainfall, and needs almost no maintenance — ideal for the Pacific Northwest.
Does moss grow on a metal roof?
Far less than on shingles or cedar. A metal roof's smooth, hard, interlocking surface gives moss and algae little to grip, so it stays cleaner in damp, shaded conditions and rarely needs the moss treatment other roofs require.
Will a metal roof rust in constant Northwest rain?
Aluminum won't — it contains no iron and cannot rust, forming a self-healing oxide layer that thrives in wet climates. That's a key reason aluminum is favored over steel in the Northwest.
How much maintenance does a metal roof need in the Northwest?
Very little — mainly an occasional rinse and keeping debris and overhanging branches clear. Unlike cedar or shingles, there's no treating, sealing, or moss-killing routine.
Sources
- CCMC 10475-R — Interlock (salt-spray & weathering tested) — Wet-climate durability
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Last reviewed 2026-07-11 · Reviewed by Scott Plumptree, Director of Marketing