Washington · Metal shingles buyer's guide

Metal shingles in Washington: how to choose

Metal shingles are steel or aluminum panels stamped to look like shingles, slate, shake or tile. The base metal is the decision that matters: steel lasts as long as its zinc or aluminum-zinc coating keeps it from rusting, while aluminum doesn't rust and weighs about a third as much. Interlock® metal shingles are aluminum, made in North America.

Reviewed by Scott Plumptree, Director of Marketing, The Interlock Group · Updated October 7, 2026

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Painted steel

Usually the lowest price

Protected by its metallic coating and paint.

Stone-coated steel

A matte, granular look

Steel underneath, with the same coating dependence.

Aluminum

Doesn't rust

About one-third the density of steel (ASM International).

The three kinds of metal shingle

"Metal shingles" covers three different products that look alike from the street and behave differently on a roof for decades. The difference is the metal underneath the paint.

Painted steel, stone-coated steel and aluminum metal shingles compared
Type	What it is	What protects it	Weight	What to watch
Painted steel shingles	Steel sheet with a metallic coating and baked paint, stamped to a shingle, tile or slate look	A zinc (galvanized) or aluminum-zinc (Galvalume) coating under the paint	Heaviest of the bare metals for the same thickness	Rust can start where the coating is cut, scratched or worn through, and at cut edges as the coating is used up
Stone-coated steel shingles	Steel shingles with stone granules bonded to the surface for a matte, textured look	The metallic coating, plus the granule layer	Heavier than painted metal	Granules can wear off in valleys and walkways; the steel underneath has the same coating dependence
Aluminum shingles	Aluminum sheet with a baked finish, interlocked panel to panel	Aluminum's own oxide film, which blocks further oxidation; there is no steel to rust	About one-third the density of steel	Aluminum can dent under large hail or foot traffic; usually costs more than steel up front

Steel coating behavior: ArcelorMittal Dofasco (Galvalume product information) and Gibraltar Building Products. Aluminum properties: ASM International. Full references at the end of the page.

Interlock® metal shingles on homes in Washington

Recent jobs in Washington in the shingle, slate and shake profiles, installed by our own company. Tap a roof to see all of its photos.

See more Washington roofs in the gallery

What matters most on a roof in Washington

Rain, moss and salt

A roof here stays wet for months, collects needles and moss under the trees, and along Puget Sound and the coast sits in salt air all year. Metal absorbs no water and doesn't rot; aluminum also has no steel for salt to rust. Moss can still settle on any shaded roof (Oregon State University Extension), so plan on keeping the roof and gutters clear.

Concealed fasteners

Exposed screws through the face of a panel depend on rubber washers that age in sun and cold, and give the wind-driven rain of winter storms a way in. Shingles that interlock with the fasteners hidden under the next course have no exposed screw heads to re-seal.

Snow and ice

Metal sheds snow, so on foothill and mountain homes plan snow guards over entries, decks and walkways before the first slide. Ice dams come from heat escaping into the attic and from ventilation, not from the roof covering; no metal shingle stops them on its own.

Who installs it

Interlocking shingles are less forgiving of poor installation than asphalt. Ask who will be on your roof, whether they are the manufacturer's certified installer, and who handles service calls.

Questions to ask any metal shingle contractor

What is the base metal, steel or aluminum, and what is its thickness?
Who is the warrantor of the material warranty, the manufacturer or the contractor, and does coverage reduce over time?
Is the finish warranty separate from the material warranty, and what does it cover (chalking, fading, peeling)?
Are the fasteners exposed or concealed?
Will my old roof come off? If you plan to roof over it, what does your inspection check first?
Is your Washington L&I contractor registration active, and will you show me your liability insurance certificate?
Is the price in writing, and what happens if you find rot once the old roof is open?

Interlock® metal shingles

We install one metal shingle system: the Interlock® aluminum roof, made in North America by Interlock Roofing at its plant in Delta, BC. Panels interlock on all four sides with the fasteners concealed, in Slate, Cedar Shingle, Shake and Mediterranean Tile, plus Standing Seam, in nine colors.

The specification: aluminum alloy per ASTM B209, 0.019-inch base metal in the Slate and Cedar Shingle profiles and 0.0276 inch in Shake and Tile (ICC-ES ESR-1790), an Alunar® PVDF finish with a 30 Year Alunar® Coating Warranty, and the Guardian Lifetime Limited Material Warranty on material and finish. Wind resistance is warranted to 120 mph when installed to manufacturer specification.

In Washington we have completed 3,219 Interlock® roofs since 1997, all installed by our own company.

Questions, answered

What are metal shingles?

Metal shingles are roofing panels stamped from painted steel, stone-coated steel or aluminum to look like asphalt shingles, slate, cedar shake or tile. They install in overlapping or interlocking courses, like shingles, rather than as long vertical sheets.

Are metal shingles good for the Washington climate?

For a house you plan to keep, they suit it well: they absorb no water, don't rot in a long wet season, shed snow, and outlast asphalt. The choice that matters most is the base metal. Steel depends on its coating to keep from rusting; aluminum doesn't rust, which matters in salt air.

Steel or aluminum metal shingles?

Steel usually costs less up front. Aluminum doesn't rust, weighs about a third as much for the same thickness, and suits roofs in salt air on the water, under firs and cedars that keep a roof damp, or anywhere you want the longest-lived option. Aluminum can dent under large hail; so can thin steel.

Do metal shingles cost more than asphalt shingles?

Yes, up front. Over 50 years the comparison usually turns, because an asphalt roof is replaced and torn off again. You get a written price for an Interlock® roof after your roof consultation; ask any asphalt roofer for theirs and compare both over the years you'll own the home.

Can metal shingles go over existing asphalt shingles?

Sometimes. A single layer of asphalt can be roofed over only if an inspection finds it suitable and local code permits. Cedar shakes, concrete tile and natural slate always come off first.

Are metal shingles noisy?

Over a solid roof deck and underlayment, which is how residential metal shingles are installed, they are not the drumming of a bare metal barn roof.

Who installs metal shingles in Washington?

Interlock Metal Roofing (PNW) Inc. installs Interlock® aluminum metal shingles from our Seattle, Bellingham and Stanwood offices, serving Washington statewide. Call (206) 589-8423 or book a free consultation at home or over Zoom.

Sources

Product specifications are the manufacturer's (Interlock Roofing). Install counts are from our own job book. Reviewed by Scott Plumptree, October 7, 2026.

Get Interlock® metal shingles priced.

A written price after your roof consultation, at your home or on Zoom. Interlock Metal Roofing (PNW) Inc. · 5608 17th Ave NW, Suite 1574, Seattle, WA 98107-5232 · 2219 Rimland Dr, Suite 301, Bellingham, WA 98226-8660 · 26910 92nd Ave NW, Suite 425, Stanwood, WA 98292