How Often Do Roofs Need Replacing in Oregon?

How long does an asphalt roof really last west of the Cascades?

The bundle wrapper says 25 or 30 years. On the wet side of Oregon the number you should plan around is closer to 15 to 20, and the reason is moss rather than storms. Multnomah and Clackamas counties average about 58 inches of rain a year, Lane County 56, Benton 60, and almost all of it falls between October and May when the sun is too low to dry a north-facing slope. A roof that stays damp for seven months grows moss, and moss roots between the granules, lifts the tab edges, and holds water against the mat underneath. Once the tabs are lifted the shingle is no longer shedding water, whatever the warranty says. Homeowners in Portland, Salem and Eugene know the cycle. Every few seasons someone washes and treats the roof, and the granules that came off with the moss wash into the gutters. Add the 36 or so freeze-thaw days Portland gets in a typical winter, which work on any tab that moss has already loosened, and 20 years is a good run for an asphalt roof in the valley. There is a second Oregon factor. Many of the Craftsman bungalows, foursquares and mid-century ranches around Portland carry a second layer of asphalt laid over the first. That layer traps heat and moisture against the old shingles below it, and it typically wears out faster than the first layer did. If your roof is a layover, the honest lifespan is shorter still, and the next job has to be a full tear-off.

How long do cedar shake, steel, tile and aluminum last in Oregon?

Cedar shake looks right on a Willamette Valley farmhouse or a coastal shingle-style home, and in a dry climate a shake roof can go 30 years. West of the Cascades it fares worse than asphalt under moss. The wood stays wet, the moss and lichen get into the grain, and the shakes cup, split and rot from the underside. Twenty years is realistic in Marion or Linn county with regular treatment, and less on a shaded lot. Steel does well inland. On the coast it has a problem.Clatsop, Tillamook and Lincoln counties take 71 to 81 inches of rain a year with gusts to 85 and 91 mph, and the wind carries salt aerosol well inland from the beach. Salt film on steel starts corrosion at every cut edge, scratch and exposed fastener head, and the fasteners usually go first. Many steel manufacturers write oceanfront exposure out of the warranty for exactly this reason, so read the exclusions before you buy a steel roof in Newport or Seaside. Clay and concrete tile last 50 years and more, but tile is heavy and most Oregon framing was never sized for it, so the roof structure often needs reinforcing before tile can go on. Aluminum sits at the durable end without the weight. It contains no iron, so it cannot rust in salt air, and interlocked aluminum shingles give moss nothing to root into. The material is rated for a 50+ year life and carries a lifetime warranty. What it does not do is make the roof invisible: aluminum can dent under a dropped ladder, flat panels can show oil-canning in low sun, and it costs more up front than the asphalt it replaces.

Does roof lifespan change between the coast, the valley, the Gorge and the east side?

Yes, enough to change what material makes sense. On the coast the enemy is salt and wind. Tillamook County's 81 inches of rain and 85 mph gusts strip granules from asphalt, and the same wind drives salt into anything ferrous. The material that lasts on an oceanfront lot in Lincoln County is one that does not rust and has no free edge for the wind to lift. In the Willamette Valley the enemy is moss and time. Rain is heavy, wind is moderate, snow is light at 7 to 19 inches a year, and roofs fail slowly from the top down. This is where asphalt and shake lifespans fall furthest short of their labels and where the wash-and-treat bill quietly adds up. The Columbia Gorge and the Mt Hood foothills add snow and sustained wind. Hood River County averages 76 inches of snow and 55 freeze-thaw days a year, and every one of those cycles pushes meltwater under a shingle edge and freezes it there. Ice dams peel asphalt and split shake in the Gorge in ways the valley never sees, and sustained Gorge wind finds any tab that has lifted. East of the Cascades in Wasco County the rain drops to 18 inches but freeze-thaw stays high at 48 days, the sun is harder on asphalt, and SB 762 wildfire hazard mapping brings home-hardening rules that favor a Class A fire-rated assembly. A roof that lasts 20 years in Eugene might last 15 in The Dalles for entirely different reasons.

How many roofs will an Oregon homeowner buy over 50 years?

Run the count for a house in Beaverton or Gresham that a family keeps for 50 years. On standard asphalt at 15 to 20 years, that is three roofs, or two and a half if you are lucky with shade and slope. Each one is a full tear-off with material, labor and disposal, plus the moss treatments in between. Architectural asphalt at 20 to 25 years still means two roofs and a third one coming due. Cedar shake in the valley is two to three roofs over the same span. Steel inland is usually one roof with fastener repairs along the way; on the coast corrosion, not wear, sets the end date. Tile is one roof if the framing can carry it. Aluminum is rated to cover the whole 50 years as a single roof, and the warranty is written that way. The Guardian Lifetime Limited Material Warranty covers the original owner for life and transfers once, with the second owner covered to 50 years from substantial completion. For a Portland homeowner the difference between three asphalt roofs and one aluminum roof is the real cost comparison, and it is why people who have already paid for two tear-offs on the same house tend to be the ones who switch.

What are the signs an Oregon roof is due, and what does the install record show?

Walk the yard after the first November storm. Granules in the gutter outlet and at the downspout splash blocks mean the asphalt is shedding its wear surface. Moss that has come back within a year of treatment means the shingles are holding water rather than draining it. From the ground, look for tab edges curling up along the north slope, shakes that have cupped or gone dark and soft, and rust streaks below fasteners on a steel roof near the coast. In the attic, daylight at the ridge, dark staining on the sheathing, or damp insulation along the eaves after a Gorge ice event all point to a roof that is past repair. A 20-year-old asphalt roof in the valley is at or beyond its working life even if it looks passable from the street, and it is better to plan the replacement in a dry August than to discover the failure in a January atmospheric river when every roofer in Portland is booked. Two layers already on the deck means the next job is a tear-off regardless. The long-life materials have a record here, not just a rating. Interlock Metal Roofing (PNW) has 374 aluminum roofs on record in Portland since 1998, 48 in Oregon City since 1996, 87 in Salem since 1999 and 64 in Eugene since 1998, with the earliest going into their fourth decade of Oregon rain. The oldest photographed roof in the Oregon gallery is a black aluminum slate in Eugene from 2017, and the most recent documented installs include a 34-square Deep Charcoal cedar-shingle-profile roof in Cloverdale in Tillamook County in April 2026, on the wettest and windiest stretch of the state. For most homeowners west of the Cascades, the question is not whether the current roof will need replacing but whether the next one will.

Common questions