Written by Tim Gaughan, Urban Edge. Published February 20, 2026.
Most asphalt shingle roofs in western Oregon last about 20 to 30 years, and the ones that fail early almost always fail at a flashing, a valley or a vent, not across the whole roof. Metal and well-kept cedar can go longer, but the real number for your house depends on the slope, the shade, the ventilation in the attic and how the details were done when it went on.
Typical lifespans, and what they assume
| Roof | Typical life in western Oregon | What it assumes |
|---|
| Asphalt shingles | 20 to 30 years | Good attic ventilation, sound flashing, moss kept off |
|---|
| Metal | 40 years or more | Fasteners and seams checked, flashing done right |
|---|
| Cedar shakes | 20 to 30 years | Regular cleaning and treatment; shade shortens it fast |
|---|
These are ranges from how roofs age here, not promises. A manufacturer's paperwork may say 30 or 50 years; that number is about the shingle in a test, not about your roof under a fir tree.
What shortens a roof in Portland
- Shade and moss. North slopes under trees stay wet for months. Moss lifts shingle edges and holds water against them.
- Poor attic ventilation. Heat and moisture trapped under the deck cook shingles from below in summer and rot the decking in winter.
- Flashing that was reused or rushed. Chimneys, skylights, walls and valleys are where water gets in first.
- Overflowing gutters. Water backing up at the eave soaks the roof edge and the fascia behind it.
How to tell where your roof stands
From the ground, with binoculars, look for:
- Shingles curling at the edges or cupping in the middle.
- Bare patches where the granules have washed off, and grit piling up in the gutters.
- Moss mats, not just a green tint.
- Lifted or missing shingles after a wind storm.
- Stains on the ceiling or in the attic, especially around the chimney or a vent pipe.
Age matters too. If the roof is past 20 years and showing two or more of these, plan for replacement in the next few years rather than repair after repair.
Repair, or plan for a new roof?
A roof with sound shingles and one bad flashing needs a repair, not a new roof. A roof that is worn across every slope needs replacing, and patching it only buys a season. Our guide to repair or replace walks through the honest checklist.
When to call a pro
Call when you see a stain inside, when shingles come off in a storm, or when you are buying or selling a house and want to know how many years are left. Please don't climb a wet roof to look; Portland roofs are slick most of the year.
We offer a free roof inspection: photos of what we find and a straight answer about repair or replacement. If the gutters are part of the problem, our gutters site covers that side.
Our work is covered by a 2-year workmanship warranty, in writing.
Book a free roof inspection or call Tim, (503) 597-8520.