Metal Roof vs. Asphalt Shingles: Best Island Roof 2026

Picking between a metal roof and asphalt shingles is the biggest choice most San Juan Islands homeowners face at re-roof time. Out here the answer isn’t the same as on the mainland. Salt air, west-side wind, and moss under the Douglas firs change the math. Here’s an honest, island-tested comparison so you can spend your money once.

For most San Juan Islands homes, a standing-seam metal roof is the best long-term value. It lasts 50 years or more, sheds our roughly 40 inches of rain a year, resists moss, and stands up to salt air when it’s coated right. Good architectural asphalt shingles are the smart pick when a tighter budget or a shorter time in the home drives the choice.

Metal roof vs. asphalt shingles: the quick comparison

The table below uses island ranges — the numbers we actually see on San Juan, Orcas, Lopez, and Shaw, where ferry trips and off-island disposal push costs above mainland jobs. Treat every figure as an estimate for planning, not a quote.

How long does each roof last on the islands?

Lifespan is where metal pulls ahead. A well-installed standing-seam metal roofing system often reaches 50 years or more in the San Juan Islands. Many homeowners put it on once and never re-roof again. Architectural asphalt shingles are rated for 25 to 30 years, but our climate is hard on them. Steady moisture, moss on north slopes, and salt air near the water pull real island life closer to 20 to 25 years. On a shady lot under old Douglas fir, expect the low end.

That gap matters because it sets the true cost of owning the roof. One metal roof can outlast two — sometimes three — shingle roofs on the same house.

What does each roof really cost out here?

Up front, asphalt shingles win. A full asphalt shingle roofing install runs about $9,000 to $24,000 on the islands. A standing-seam metal roof lands between $14,000 and $45,000 or more, depending on size, pitch, panel profile, and access. Both prices include ferry staging for crews and materials, plus hauling old roofing off-island. That’s why an island re-roof costs more than the same job in Anacortes.

Cost per year tells the more useful story:

• Metal: spread across a 50-plus-year life, even a $30,000 roof works out to about $250-$600 a year.
• Asphalt: a $16,000 shingle roof replaced every 20-25 years lands closer to $400-$1,000 a year once you count a second replacement.

Add the moss treatments and repairs shingles need on shaded island roofs, and metal looks even better over the long run. Neither is “cheap,” but they answer different questions: the smallest check today, or the lowest cost over the life of the home.

Which holds up better to salt air and west-side wind?

If your home sits near saltwater — think Roche Harbor, Deer Harbor, or a Lopez shoreline — this is the deciding factor. Salt air rusts ordinary metal and wears out fasteners, so we use marine-grade Kynar 500 / PVDF coatings on 24-gauge steel with corrosion-resistant fasteners. Built that way, metal shrugs off salt that would age other materials fast.

Wind is the other island fact of life. The west side sees gusts about 20% stronger than Anacortes, and the worst weather peaks in November. Interlocking standing-seam panels give wind almost no edge to grab, so they do great on exposed, waterfront, and ridgetop homes. Asphalt shingles hold up well with proper nailing and starter courses, but single tabs can lift or tear in the strongest west-side gusts. That’s exactly the damage our storm and emergency repair crews get called for after a big blow.

Which roof resists moss and 40 inches of rain?

Both roofs shed our 40 inches of rain a year when flashing and slope are done right. This is the Pacific Northwest, so good drainage is a must. The difference is moss. A metal roof’s smooth surface gives moss and algae almost nothing to grab, and debris slides off shaded slopes instead of rotting into a green mat.

Asphalt shingles are the opposite. Their gritty surface and the shade of north slopes under Douglas fir are perfect for moss. You can manage it — moss treatment and roof cleaning plus zinc or copper ridge strips keep it in check — but that’s ongoing upkeep metal mostly skips. Two rules apply to either roof. Put a zinc or copper strip near the ridge so rain carries metal down the slope. And never pressure-wash shingles — it strips the protective granules and shortens their life.

Repairability and curb appeal

Shingles are easier and cheaper to repair. A small leak or a few wind-torn tabs are a quick, low-cost fix — swap the bad shingles and move on. Metal needs repairs less often, but they take more skill. A damaged panel usually means matching color and profile, not patching, so the right installer matters more.

Looks come down to taste. Metal reads clean and modern, fits farmhouse and modern island homes, and comes in many Kynar colors that hold their finish for decades. Architectural shingles bring depth and a traditional texture that blends into wooded lots around Eastsound, Olga, and Friday Harbor. Both look good. Neither is “better” here.

The verdict: which should you choose?

Choose standing-seam metal if this is a forever-home, if you’re near saltwater, or if you never want to think about your roof again. It’s the best long-term island roof. The long life, moss resistance, and salt-and-wind toughness are worth the higher up-front cost, and the cost-per-year math usually favors it over the life of the house.

Choose quality architectural asphalt shingles if budget is the main limit, if you expect to sell within five to ten years, or if you want a traditional look that fits the neighborhood. Well-installed architectural shingles are an honest, solid roof for our climate. They just ask for a bit more upkeep and an earlier replacement.

Still on the fence? That’s normal, and it’s exactly what a roof replacement consultation is for. We’ll look at your slopes, exposure, shade, and budget and give you straight repair-or-replace advice — not a sales pitch.

Get your real number

Both price ranges above are for learning only — an estimate, not a quote. The free on-island inspection is where you get your real number, because your roof’s size, pitch, access, and exposure decide the cost. As a licensed, bonded, and insured WA roofing contractor serving all of the San Juan Islands, we back our work with a workmanship warranty.

Ready to compare options for your home? Contact us or call (360) 205-1462 to schedule a free inspection and written estimate anywhere on San Juan, Orcas, Lopez, or Shaw.