Metal Roofing in Lewis and Clark, Oregon — Lifetime Interlock® Aluminum Shingles Installed Locally

Aluminum panels shed snow and ice efficiently because their smooth, hard surface prevents moisture from adhering the way asphalt does, reducing ice dam formation in your region's roughly 120 cm annual snowfall. Interlock's four-way interlocking system and engineered profiles grip snow safely without traditional gutters backing up. With about 120 freeze–thaw days per year here, this matters: asphalt absorbs meltwater and fails during repeated cycles, while aluminum's oxide layer simply darkens but never rots or weakens. Snow guards are available if you need them, and the lightweight design—the Shake profile weighs just 0.58 lb/sq ft—distributes loads evenly so no structural reinforcement is needed.

Asphalt absorbs water into its porous surface; when frozen, water expands and cracks the shingle, which then absorbs more water next thaw cycle, accelerating failure. Aluminum contains no iron and its self-healing oxide layer prevents rust and water infiltration regardless of Clatsop County's approximately 120 freeze–thaw days annually. With about 214 mm of rain and recurring freezes, this cycling is relentless on asphalt. Interlock panels are manufactured from 3105-H24 / 3003-H24 roofing-grade aluminum alloy (ASTM B209), a material chosen precisely because it survives harsh maritime climates—the company has been installing since 1998 and operates everything from coastal salt-air homes to an Antarctic research station. Your roof stays functionally intact for decades.

Yes—Interlock's four-way interlocking aluminum panels are warranted to resist wind speeds up to 120 mph (193 km/h), well above the gusts around Lewis and Clark. Regional daily-max winds average about 27 km/h with occasional gusts to 100 km/h, well within the design envelope. The interlocking system distributes lateral stress across multiple panels rather than relying on fasteners alone, and ICC-ES evaluation report ESR-1790 (reissued 2025) confirms compliance with IBC/IRC wind requirements. Because aluminum weighs almost nothing compared to slate or tile, wind pressure against the roof surface is minimized—the Slate profile installs at roughly 0.41 lb/sq ft. Coastal installers in British Columbia and Washington have proven this system in far windier, saltier conditions.

Aluminum cannot rust because it contains no iron, the element that oxidizes into rust. Instead, a microscopically thin oxide layer forms on bare aluminum and actually heals itself when scratched—a built-in defense mechanism that asphalt and steel lack. Interlock coats both sides of every panel with Alunar 70% PVDF fluorocarbon finish (the Alunar coating is warranted 30 years against chalking and fading per ASTM D4214/D2244), adding a durable barrier against Clatsop County's ~214 mm annual rainfall and salt air if you're near the coast. The Guardian warranty covers rusting as a material defect for the original owner's lifetime and the next owner's first 50 years. Steel roofing rusts within years in this climate; aluminum panels installed here in 1998 are still standing because corrosion simply isn't possible.

No structural reinforcement is needed—that's one of aluminum's defining advantages. Interlock's Mediterranean Tile profile, which replicates traditional clay or concrete tile, weighs approximately 0.59 lb/sq ft, making it about 96% lighter than genuine clay or concrete tile. Many Lewis and Clark homeowners can install Interlock directly over their existing asphalt roof, eliminating expensive tear-off and disposal costs. Your home's existing framing was built to carry asphalt or wood shingles; aluminum panels are so light that they add negligible load even on older structures. This matters in regions with 120 cm of annual snow—the lightweight material doesn't compress under snow load the way heavier materials do, and the reduced overall weight means better load distribution and longer structural life for your home.

Interlock panels carry UL 2218 Class 4 impact rating—the highest available—and the Guardian warranty covers perforation from hailstones up to 1.5 inches. Class 4 rating means the roof survives repeated impacts that would dent or puncture asphalt shingles, which typically achieve Class 1 or 2. Many insurance companies recognize metal roofs' impact resistance and offer discounts on premiums; contact your agent with the UL 2218 Class 4 certification for specific quotes. Hail isn't frequent in Lewis and Clark's climate, but when severe weather does occur, an asphalt roof often requires costly replacement afterward, while aluminum's hardness and four-way interlocking system mean the roof survives intact. Over the roof's lifetime—potentially 50+ years with aluminum versus 15–20 with asphalt—impact durability translates to lower total insurance and replacement costs.

Yes, if you choose an energy-efficient color. Certain Interlock finishes reflect rather than absorb solar heat, with thermal emissivity of 0.84 and initial solar reflectance up to 0.55 (such as Aged Copper Penny), meaning they stay cooler under sun and emit absorbed heat more efficiently. Lewis and Clark receives about 3561 sunshine hours annually—enough to make reflectance meaningful over the summer season. Cool Roof Rating Council-rated colors reduce the heat your air conditioning must remove, lowering cooling costs. In winter, this reflectance doesn't reduce heating—your home's insulation layer, not the roof finish, controls interior warmth. The Alunar fluorocarbon coating (30-year warranty) maintains reflectance as it ages, unlike faded asphalt that darkens over time. Over decades, energy savings from a reflective metal roof compound into substantial utility cost reductions.

How long will a metal roof actually last, and what does the warranty cover?

A metal roof requires minimal maintenance—no algae treatment, no shingle replacement, no wood staining. Quarterly gutter clearing and an annual rinse to remove moss or pollen (common in regions with ~214 mm annual rain) are standard; that's it. Asphalt shingles need algae and mold treatment as they age and absorb moisture, and wood shingles or shakes demand staining, repair, and moss removal. Interlock's four-way interlocking aluminum design prevents debris accumulation and water pooling where maintenance issues begin. CALGreen-verified for reduced maintenance means the design itself minimizes upkeep. Lewis and Clark's wet climate accelerates asphalt deterioration and wood rot, making routine maintenance for those materials frequent and costly. A metal roof's hard, non-porous surface sheds water quickly, preventing the moisture-related failures that drive maintenance cycles for traditional materials. Over 50 years, maintenance savings alone justify the initial investment.

Aluminum is approximately 95% recyclable, so an Interlock roof at end-of-life returns to the material stream rather than a landfill. Asphalt shingles—the dominant roofing material—are tear-torn-off and landfilled millions of tons annually because the asphalt binder prevents recycling. Interlock panels, manufactured in Delta, BC since 1998 using proven processes, are lighter and faster to install than slate or tile, meaning lower installation fuel consumption. When you replace an asphalt roof, disposal costs and landfill volume are real—in regions like Clatsop County with ~214 mm annual rainfall, asphalt deteriorates faster, meaning more frequent replacements and more waste. Choosing aluminum breaks that tear-off-and-landfill cycle: your roof becomes a durable asset rather than future waste. At end-of-life, aluminum's inherent recyclability means the material feeds back into manufacturing—new roofs, windows, or automotive components—rather than sitting in a landfill for decades.