Western red cedar shake.
Cedar shake is the material the Pacific Northwest was meant to wear. It is the material on the first roof Henrik installed in Lake Oswego in 1996, and it is the material on the 1928 English cottage that anchors the homepage of this site. Wyatt Olafsson has run every Cascade cedar shake job since 2013. We install roughly sixty to seventy cedar shake roofs a year — about a quarter of our residential volume.
The product itself is Western red cedar — Thuja plicata — grown on the Pacific slope of British Columbia and the Olympic Peninsula. We install Cedar Shake & Shingle Bureau Certi-Split #1 Grade hand-split-and-resawn shakes, twenty-four inches in length, with a half-to-three-quarter-inch butt thickness. The shakes are hand-split on the face for the textured appearance and re-sawn on the back for a flat installation surface. They are sourced from three Canadian mills we have used since 2008.
The shake field is laid at a five-to-five-and-a-half-inch exposure on a synthetic underlayment, with thirty-pound felt interlayment between courses (the “double-roof” method specified by CSSB for premium installations). Stainless ring-shank nails. Copper drip edge where the homeowner wants the upgrade. Zinc strips at the ridge for moss prevention.
Pricing.
Forty-five to sixty years.
A properly installed CSSB Certi-Split #1 Grade cedar shake roof in Lake Oswego, Beaverton, or comparable Portland metro climate routinely lasts forty-five to sixty years. The variance is moss management. With a zinc strip at the ridge plus a low-toxicity moss treatment every three to five years from year ten onward, the upper end of that range is realistic. Without moss management, cedar can drop to thirty years in heavily-shaded east-facing situations.
In coastal climates — Bainbridge Island, the Oregon Coast, Astoria — untreated cedar should not be specified. Salt air shortens the life materially. For coastal homes we install CCA-pressure-treated cedar with copper drip edge throughout, and we expect thirty-five to forty-five years of service life in those conditions.
Provenance and spec.
Four projects from the last year.
Lake Oswego · 2,400 sqft
CSSB #1 · Hand-split & resawn · 24" length · October 2025
Bainbridge Island · 2,950 sqft
CCA-treated · Coastal spec · Copper drip edge · March 2025
McMinnville · 1,950 sqft
CSSB #1 · 5.5" exposure · Zinc ridge strip · February 2025
West Linn · 3,100 sqft
CSSB #1 · 24" graduated · Copper gutters · November 2024
Questions we hear most.
How long does cedar shake last in the Pacific Northwest?
Forty-five to sixty years for a properly installed CSSB Certi-Split #1 Grade cedar shake roof in Lake Oswego or comparable Portland metro climate, on a properly ventilated underlayment, with periodic moss treatment in the third decade onward. Without moss treatment, lifespan can drop to thirty years on east-facing shaded elevations.
Is cedar shake a fire risk?
Untreated cedar shake is Class C fire-rated. CCA-pressure-treated cedar (which we install in any wildland-urban-interface zone, including most of Hood River County, much of Bend, and certain Coast Range jurisdictions) is Class A. Most of the Portland metro does not require treated shake; check your jurisdiction’s building code before specifying.
Cedar shake versus synthetic shake — which is better?
Synthetic shake (Brava, DaVinci, CertainTeed Symphony) is the right answer for fire-restricted areas and for owners who do not want the periodic moss treatment. The synthetic looks acceptable from the street, lasts a similar duration, and costs a bit less. Natural cedar reads correctly on a Pacific Northwest 1900s-1940s home in a way no synthetic does — the way light moves through the irregular splits is not something a mold can replicate. We install both, and we will be honest with you about which is right for your home and the architectural register you are trying to preserve.
Do I need to treat the moss on a cedar roof?
Every three to five years from year ten onward. We install zinc strips at the ridge as standard, which slows moss growth considerably. We apply a low-toxicity moss treatment in October each year on the homes we maintain. Cascade does not run a maintenance crew — we recommend two Portland-area firms that do, and we’ll give you the names. Without moss treatment, cedar lifespan can drop from fifty years to thirty in heavily-shaded conditions.
Request a cedar shake site visit.
Wyatt and Henrik will both come to a cedar consultation if you ask. We’ll bring sample shakes.