Buyer's Guide
How to choose a metal roofing contractor in Washington
Ask every contractor five questions: how the panels attach to the deck, whether the fasteners are exposed or concealed, what the coating actually is, whether the warranty is manufacturer-backed and transferable, and how many metal roofs the crew installed last year. Those five separate the systems faster than any price comparison. Three more checks below verify what you are told — and they work on any company, including us.
1. Ask how the panels actually attach to your roof
Start here, because the answer tells you what the roof is. Interlock slate and cedar-shingle panels carry a full-length nailing tab across the top edge, pre-punched for four fasteners driven directly into the deck — not a single corner tab, and no separate clips — and then lock to their neighbours on all four sides. That combination is what the warranted 120 mph wind rating and the ICC-ES ESR-1790 uplift rating of 177.5 psf are measured on. If a contractor cannot describe the attachment in that much detail, they are quoting a panel, not a system.
2. Ask whether the fasteners are exposed or concealed
Exposed gasketed screws driven through the weather surface are the cheapest way to hang metal and the first thing to fail. The gaskets harden, the screws back out under thermal cycling, and every head is an entry point — a real problem through a Puget Sound winter and worse where foothill freeze-thaw works on it in North Bend, Enumclaw and Buckley. On saltwater exposure around the Kitsap Peninsula and the islands, mismatched fastener metals add galvanic corrosion to the list. Concealed-fastener, four-way interlocked panels with corrosion-matched trim avoid all of it. If the answer involves visible screws, ask what maintenance looks like in year twelve.
3. Ask what the coating actually is — and what metal is underneath it
Coating and substrate are two separate questions, and both decide how long the roof lasts here. Ask for the resin by name: a 70% PVDF finish to AAMA 2605 (the Kynar 500 family, which Alunar® belongs to) holds color and chalk resistance far longer than the polyester coatings common on budget panels. Then ask what is under it. Aluminum cannot rust. Steel — including stone-coated steel — corrodes at cut edges and at any scratch that breaks the coating, which is the decisive distinction in salt air off the Salish Sea and the Strait of Juan de Fuca from Bellingham and Anacortes to Sequim and Port Orchard.
4. Ask whether the warranty is manufacturer-backed, and whether it transfers
A contractor-written warranty is worth exactly as long as the contractor lasts. Ask who issues it, and get the answer in writing. The Guardian Limited Material Warranty is issued by the manufacturer, Interlock Roofing Ltd.: lifetime coverage to the original owner, one transfer, and the second owner covered to 50 years from substantial completion when the roof is registered within 60 days. Wind is warranted to 120 mph and hail to 1.5 inches, with the Alunar® coating covered 30 years. Then ask the questions that catch the fine print: Is it prorated? Is there a salt-air or coastal carve-out? What does the transfer cost, and who files it?
5. Ask how many metal roofs the crew installed last year
Metal is a trade of its own, and an occasional metal job on an asphalt crew shows up in the flashing details. Ask for the count, ask which towns, and ask to see one. Our record is countable rather than rhetorical: 3,223 completed Washington installs since 1997, 3,092 of them pinned on the public project map, and 394 in Seattle alone since 1998. Three Washington offices — Seattle, Bellingham and Stanwood — mean the crew that quotes your roof works your county regularly.
6. Verify the Washington contractor registration before anyone climbs a ladder
Washington requires contractors to be registered with the Department of Labor & Industries, and you can verify any registration, bond and insurance status in seconds through L&I. A contractor should hand you the number without being asked. Ours is published in the footer of every page of this site: Washington #INTERMR75406. Check the status, the bond, and how long the registration has been continuously active — a number that resets every few years is telling you something.
7. Demand documented installs and third-party reviews, not a testimonial page
Any roofer can show a photograph. What matters is whether you can see where the roof went on, what system it is, and how it is aging. Ask for a photo record tied to real locations, then check reviews the contractor cannot edit — Google, BBB, and independent survey platforms such as GuildQuality where every response is tied to a completed job. Read the middling ones; how a company handles a scheduling complaint tells you more than ten perfect reviews. Ours is public: 215 Washington gallery photos tagged with city, system and color, and more than 750 approved Washington reviews.
8. Expect straight answers on moss, salt air, snow and wildfire
A Washington quote should address Washington roofs. West of the Cascades, ask what ends the moss cycle — moss roots into asphalt granules and cedar fiber, and a smooth aluminum field gives it nothing to hold. On the water, ask what happens at a cut edge in salt air. In the foothills, ask how the assembly sheds snow and whether anything up there can be worked loose by freeze-thaw. East of the crest and in the wildland interface, ask whether a Class A fire-rated assembly is available (ASTM E108, with GAF VersaShield per ICC-ES ESR-2053) — the roof is the largest surface you can make non-combustible. A contractor with no answer on these is quoting a roof for somewhere else.
Contractor-vetting questions, answered
What questions should I ask a metal roofing contractor?
Five, in this order: How do the panels attach to the deck? Are the fasteners exposed or concealed? What exactly is the coating, and what metal is under it? Is the warranty manufacturer-backed, and does it transfer? How many metal roofs did your crew install last year? Specific answers to all five are rarer than you would expect — and the gaps are the point.
How do I choose a metal roofing contractor in Washington?
Ask the five questions above, then verify the answers. Confirm the contractor registration with Washington L&I, ask for documented installs in your town, read third-party reviews on Google, BBB or GuildQuality, and check the manufacturer ICC-ES evaluation report number yourself. Our Washington registration is #INTERMR75406 and it is published in the footer of every page.
What's the difference between an installer and a certified installer?
Certification means the manufacturer trained the crews, stands behind the installation, and registers the warranty. We are Washington's authorized Interlock® installer, registered in Washington under #INTERMR75406 and working from offices in Seattle, Bellingham and Stanwood. The manufacturer's engineering and our Pacific Northwest install record since 1997 come as one package.
Should I get multiple metal roofing quotes?
Yes — and normalize them before comparing. A cheaper quote with exposed fasteners, a prorated warranty and a steel panel headed for salt air on the Salish Sea is not the same product at a lower price; it is a different and shorter-lived roof. Compare systems, warranties and documentation first, then compare price.
Ready when you are — bring this checklist to the estimate.
