Materials Guide
The Best Roofing Materials for Pacific Northwest Weather.
Quick Answer
For most PNW homes, shingle-based roofing systems (architectural asphalt or composite) offer the best balance of cost, lifespan, and weather performance. Standing-seam metal is the best long-term option (40+ years, sheds PNW rain, resists moss) but costs roughly twice as much. Plastic-based membranes (TPO, PVC, EPDM) are the right call for flat or low-slope sections. Skip natural cedar shake for new installs unless you have a specific reason.
What PNW weather actually does to roofs
To pick the right roof, it helps to understand what's specifically working against it here. The Eugene/Springfield area gets 40–50 inches of rain per year, most of it falling between October and May. Summers are dry. Snow is occasional. The real wear factors are:
- Sustained moisture. Months of damp conditions accelerate degradation of porous materials and feed biological growth.
- Moss and algae. Cool, shaded, damp = ideal moss conditions. Moss lifts shingle tabs and traps water against the roof surface.
- UV cycling. Dry, sunny summers cycle UV exposure that's hard on asphalt and natural wood.
- Tree litter. Doug fir needles, big-leaf maple leaves, and moss spores fall on roofs constantly.
- Wind. Less of a factor here than the Gulf Coast or Plains states, but Valley wind events still test fastener quality.
Different materials handle these factors very differently.
Material options, side by side
| System | Lifespan in PNW | Moss resistance | Up-front cost | Best for |
|---|---|---|---|---|
| Shingle-based (architectural asphalt) | 20–30 years | Fair–Good | $$ | Most pitched residential roofs |
| Shingle-based (composite / synthetic) | 20–30 years | Very good | $$$ | Premium homes wanting a slate or shake look |
| Standing-seam metal | 40+ years | Excellent | $$$$ | Modern, farmhouse, rural, long-haul ownership |
| Plastic-based membrane (TPO / PVC / EPDM) | 20+ years | Excellent | $$ – $$$ | Flat or low-slope sections |
| Cedar shake (natural) | 10–20 years | Poor | $$$$ | Historic homes only, with eyes-open maintenance |
Shingle-based roofing systems — the PNW workhorse
The vast majority of residential roofs we install are shingle-based. Within this category, there are two paths:
- Architectural asphalt shingles are the everyday workhorse — 30–50 year manufacturer warranties, strong PNW track record, excellent value, and a deep range of profiles and colors. Look for algae-resistant (AR) products with copper or zinc granules; they keep PNW roofs looking clean for decades.
- Composite or synthetic shingles (sometimes called "designer" shingles) deliver the visual texture of slate or cedar shake with modern manufacturing's durability. Excellent moss resistance, 20–30 year lifespans, and a top-shelf look. Cost is about 1.5–2× architectural asphalt.
Standing-seam metal — the long-haul play
Standing-seam metal is the best-performing pitched-roof material for the PNW, full stop. The smooth surface sheds rain and prevents moss colonization. Lifespans of 40+ years are standard. The premium is real (roughly 2× shingle-based) but amortized over decades — and metal roofs often pay back at resale. A great fit for modern, farmhouse, and rural-residential homes.
Plastic-based roofing systems (TPO, PVC, EPDM) — for flat and low-slope sections
Single-ply plastic membranes are the right tool for flat or low-slope roof sections — additions, sunrooms, porch covers, garages, or low-slope main roofs that shingle systems can't reliably waterproof. The three common membranes — TPO (thermoplastic polyolefin), PVC, and EPDM rubber — all dramatically outperform old-school rolled-asphalt roofing in lifespan, leak resistance, and seam reliability. Expect 20+ years from a properly installed membrane, with excellent moss resistance thanks to the smooth, non-porous surface.
Cedar shake — usually not the right call anymore
Real cedar shake has the natural texture some homeowners love, but in PNW conditions it's hard to recommend for new installs. Moss colonizes cedar aggressively; lifespan is shorter than you'd expect for the price; and modern composite shingles get most of the look at half the maintenance.
Picking the right one for your home
Quick framing by home type:
- Craftsman bungalows: Shingle-based — architectural asphalt in a darker color, or composite for a cedar-shake look without the maintenance.
- Modern PNW contemporary: Standing-seam metal in a dark charcoal or matte black.
- Farmhouse / rural residential: Standing-seam metal or premium shingle-based.
- Mid-century ranch: Shingle-based architectural asphalt — clean, low-profile, cost-effective.
- Historic / period homes: Shingle-based with a heritage profile, or composite slate.
- Flat-roof additions, sunrooms, low-slope porches: A plastic-based membrane (TPO, PVC, or EPDM).
PNW-specific features worth paying for
- Algae-resistant granules. Standard or near-standard on architectural lines. Worth it everywhere in the PNW.
- Synthetic underlayment. Outperforms traditional felt in wet conditions.
- Ice-and-water shield at valleys and eaves. Required in many jurisdictions, valuable everywhere.
- Proper ventilation. Critical to keep the underside of the roof deck dry. Pays back in shingle life.
- Zinc strip at the ridge. Slowly releases zinc when it rains, killing moss spores. Cheap insurance for asphalt roofs.
FAQs
Will moss really damage my roof?
Yes. Moss colonies hold moisture against the roof surface and physically lift shingle edges. Left unaddressed, moss can shorten an asphalt roof's lifespan by 20–40%.
Are metal roofs noisy in the rain?
No — not on a properly installed residential roof. Standing-seam metal sits over decking and underlayment that effectively dampens sound. The "tin roof" rain noise is a barn-roof phenomenon, not a residential one.
Should I power-wash moss off my old roof?
No — pressure washing can damage shingles and strip granules. Use a soft-wash treatment or have a professional roof cleaner handle it. Better yet, prevent moss with proper materials, ventilation, and a zinc strip at the ridge.
How much more does metal cost than asphalt?
Roughly 2–2.5× the cost of architectural asphalt for a comparable home. See our asphalt vs. metal comparison for a detailed breakdown.