Metal Roofing in Markham, Oregon — Lifetime Interlock® Aluminum Shingles Installed Locally

Markham Metal Roofing Experts Installing Lifetime Interlock® Aluminum Shingles Since 1997

Metal Roofing Built for Markham's Heavy Rain, Snow Loads, Windstorms & Lifetime Protection

Interlock Metal Roofing (PNW) Inc. is Markham, Oregon’s trusted local metal roofing contractor, proudly serving homeowners since 1997. As the exclusive authorized installer of Interlock® Lifetime Aluminum Roofing Systems, we deliver unmatched performance, beauty, and durability tailored for the Pacific Northwest’s unique climate. Markham’s heavy rainfall, winter snow, and seasonal temperature swings demand a roof engineered for superior protection—our heavy-gauge, fire-resistant, and energy-efficient cool roofs are designed to shed snow, resist moss, and withstand high winds. Choose from the timeless elegance of slate, cedar shingles, shake, Mediterranean tile, or standing seam profiles, all protected by the advanced Alunar® Coating System and backed by a Lifetime Warranty. For roof replacement or re-roofing in Markham, trust Interlock Metal Roofing (PNW) Inc. for a roof that’s built to last and enhance your home’s curb appeal.

Interlock metal roofing styles including slate, cedar, shake, tile, and standing seam in Markham, Oregon

Performance you can measure (all climates)

Wind- and storm-resistant Interlock® metal roof rated to 193+ km/h for Markham, Oregon

Weather Resistant

Tested to 193+ km/h (120 mph) winds

Interlock® aluminum metal roof in Markham, Oregon backed by a Lifetime-Limited, transferable warranty

Durable

Lifetime-Limited, transferable warranty

Energy-efficient cool-roof Interlock® aluminum metal roofing in Markham, Oregon

Energy Efficient

Reflective cool-roof lowers cooling costs

Rain- and moisture-proof Interlock® metal roof for Markham, Oregon

Rain & Moisture Proof

Repels ~1468 mm of rain a year

UL 2218 Class 4 impact- and hail-resistant Interlock® metal roof in Markham, Oregon

Impact Resistant

UL 2218 Class 4 — top hail rating

Corrosion- and rust-proof aluminum Interlock® metal roof for Markham, Oregon

Corrosion Resistant

Aluminum won’t rust or corrode

  • Authorized Interlock® installer serving homeowners in Markham and throughout Multnomah County
  • Alunar® Coating System provides a continuous, finished surface with no visible aluminum and strong corrosion resistance in damp Pacific Northwest air
  • Precision weatherproof seams (profiles: slate, cedar, shake, tile) and mechanical fastening (profile: standing seam) deliver long-term leak protection during wind-driven rain events common to Markham’s wet seasons
  • Interlocking panels tested to 193+ km/h (120+ mph) for severe wind events that can occur across Multnomah County
  • Engineered installation resists prolonged rainfall from atmospheric river storms that impact Markham and nearby lowland areas
  • Roof geometry promotes rapid snow-shedding to reduce buildup and mitigate ice-dam risk during occasional inland freeze–thaw cycles
  • Class A fire-rated available to improve ember resistance and roof performance during dry-season wildfire exposure in parts of Multnomah County
  • UL 2218 Class 4 impact resistance reduces damage from hail, falling branches, and windborne debris
  • Durable Alunar® finish resists airborne salts carried inland during strong coastal storms, providing extra corrosion protection for Markham properties
  • Cool-roof performance lowers heat gain in summer, improving attic comfort and reducing peak cooling loads during regional heat events
  • Solar-compatible flush profiles accept modern bracket-mounted photovoltaic systems without compromising weatherproof seams
  • Recyclable aluminum construction minimizes landfill waste and supports sustainability goals for Multnomah County homeowners
  • Low-maintenance surface resists biological buildup; moss-prone roofs in damp Markham microclimates are easier to clean and inspect
  • Architectural profiles replicate slate, cedar shake, and tile to match regional aesthetics while meeting local building practices
  • Backed by a Lifetime-Limited transferable warranty to protect long-term value for Markham residences

Metal roofing built for Markham's climate

Averages (10-yr): ~1468 mm rain and 48 cm snow per year, ~2957 sunshine hours, mean 11.5°C, typical daily-max winds ~15 km/h with gusts to 116 km/h, and ~36 freeze–thaw days per year.

  • 48 cmavg. snow / year
  • 1468 mmavg. rain / year
  • 36freeze–thaw days / year
  • 116 km/hpeak wind gusts
  • 2957 hrsannual sunshine
  • 11.5°Cmean temperature

Interlock® aluminum roofing is engineered for these conditions — wind-rated to 193+ km/h (120 mph), UL 2218 Class 4 impact-rated, Class A fire-rated, and built to shed snow and resist ice dams and freeze–thaw cracking, backed by a lifetime limited warranty.

Interlock Metal Roofing (PNW) Inc.

Hours

  • Monday9:00 AM – 5:00 PM
  • Tuesday9:00 AM – 5:00 PM
  • Wednesday9:00 AM – 5:00 PM
  • Thursday9:00 AM – 5:00 PM
  • Friday9:00 AM – 5:00 PM
  • SaturdayClosed
  • SundayClosed

Interlock Metal Roofing (PNW) Inc. – Oregon is a trusted metal roofing contractor proudly serving homeowners and businesses across Oregon. With decades of proven roofing experience, Interlock has earned a reputation for exceptional craftsmanship, long-term reliability, and outstanding customer care. As a specialized installer of premium aluminum and standing seam metal roofing systems, Interlock is the exclusive authorized installer of Interlock® lifetime roofing products engineered to perform in Oregon’s diverse climate — from coastal rain and wind to mountain snow and high-desert heat. Built on integrity, professionalism, and superior workmanship, Interlock Metal Roofing (PNW) Inc. has completed thousands of successful roofing installations throughout the region, helping Oregon property owners invest in roofs that are both beautiful and built to last. Our team is known for transparent communication, efficient project execution, and meticulous installation standards, supported by industry-leading materials and strong warranty protection. Interlock’s commitment to excellence is reflected in its dedication to safety, ongoing installer training, and recognition through regional industry awards and customer satisfaction accolades. With highly trained crews and strict adherence to best practices, we deliver durable, energy-efficient roofing solutions that enhance home value and protect against the elements for decades. Whether you need a residential metal roof replacement, a commercial roofing upgrade, or a custom architectural metal roofing system, Interlock Metal Roofing (PNW) Inc. is Oregon’s trusted choice for premium lifetime metal roofing — combining proven expertise, exclusive products, and service you can count on.

Recognition GuildQuality Guildmaster Award — verified customer satisfaction (GuildQuality)

Accredited BBB Accredited A+

Part of the Interlock® certified installer network →

Get a Free Metal Roof Estimate in Markham, Oregon

Interlock® Aluminum Roofing — all-climates performance specs for Markham, Oregon

Spec / RatingClimate / Risk Factor + What It Solves
Wind resistance: 120+ mph (193+ kph)Extreme wind, hurricanes, storm uplift: full interlocking attachment helps prevent blow-offs, edge lifting, and panel loss in high-gust events.
Fire rating: Class A (with proper assembly)Wildfire, embers, radiant heat, chimney sparks: non-combustible roof assembly provides the highest residential fire protection rating.
Hail resistance: UL 2218 Class 4Hail and impact debris: highest impact classification; resists cracking, splitting, and surface loss common with asphalt under hail strikes.
Snow & ice performance: interlocking, shedding profileHeavy snow, freeze-thaw, ice dams: smooth aluminum sheds snow efficiently and the interlocking design helps block water intrusion when melt-refreeze cycles occur. (Final snow-load capacity depends on roof structure and local code.)
Corrosion resistance: aluminum (won’t rust)Salt air, coastal humidity, wet climates: aluminum naturally resists rust and corrosion, reducing long-term failure risk in marine or high-moisture environments.
Heat / UV durability: baked-on coating systemHigh heat, intense sun, thermal cycling: coatings resist UV breakdown and temperature-swing fatigue, slowing fading and surface degradation.
Moss / algae resistance: smooth coated surfaceWet shade, organic growth: low-porosity metal surface gives moss/algae less to grip, reducing staining and maintenance.
Material: heavy-gauge aluminum roof profiles (Slate / Shake / Shingle / Tile / Standing Seam)All-season structural stability: lightweight, dent-resistant metal system stays stable through large hot-cold swings and severe weather.
Expected lifespan: 50+ yearsLong-term durability across climates: avoids re-roof cycles typical of shorter-life materials, even in high-stress environments.
Warranty: Lifetime-Limited, non-prorated + 50-year transferableLifetime protection + resale value: guarantees long-term material confidence and transfers to future owners.

Available Profiles in Markham, Oregon:

Explore all Interlock® metal roofing systems, or see the Guardian lifetime warranty and independent testing reports.

Completed Interlock® metal roofs near Markham, OR

Every marker is a real, anonymized Interlock® aluminum roof completed by a Certified Interlock Installer. Explore verified Interlock® installations near Markham, Oregon, United States on the interactive project map and photo grid — filter by roof profile (Slate, Cedar Shingle, Shake, Mediterranean Tile, Standing Seam, Solid Copper), colour and year of completion.

4.6 / 5 — from 777 verified customer reviews in Oregon

What our customers are saying:

★★★★★
Review: August 15, 2022Completion: June 30, 2022

We had a gorgeous Red Shingle Interlock roof installed and it had completely changed the look of our house! This roof was a long time coming…we placed the order in September 2021 and knew there was a 6mo wait but we were determined to wait it out and it was so worth it!The crew worked so fast and efficiently and really did a fantastic job. They were also super clean and made a great effort to leave no mess behind and even took care not to crush my plants.This is an expensive roof, make no bones about it, but the quality and durability as well as the beautiful look all are worth it.My house has had so many complements since it was done and compared to my neighbor next door who had a roof put on a couple months ago with traditional shingles, it is clear my roof is the favorite of the block!! Positive Responsiveness, Punctuality, Quality, Professionalism, Value Services Attic venting, Attic venting repairs, Roof installation

★★★★★
Review: November 15, 2023Completion: October 11, 2023

Interlock roofing is a fantastic company and the representative, Damon, was incredible. Always there to answer questions in a quick timely manner. I couldn’t be happier. This Aluminum roof will never need to be replaced and it makes my simple home look like a million dollar home. It’s stunning. I chose black slate and it is so beautiful. Such peace of mind too. I would highly recommend this company and its employees. The installation crew were professional and careful and accommodating. Thank You Damon and Interlock Roofing. Positive Responsiveness, Punctuality, Quality, Professionalism, ValueServices, Attic venting, Roof installation

★★★★★
Review: May 5, 2021Completion: April 14, 2021

We had decided that we were ready to invest in a metal roof in our "forever home" for, among other reasons, its durability, eco-friendlly recyclable materials and light weight for seismic concerns. Damon was punctual and professional and an excellent salesperson. We had a very positive experience with May regarding scheduling; she was able to accommodate our timeframe and the crew showed up earlier than anticipated. The workmen were professional and very fast, and completed the tear-off and roof installation in 2.5 days. We were very impressed. The new roof is extremely attractive, and provided the whole house with the equivalent of a much needed "facelift!" We are delighted with our new roof and enjoy it every time we step away from the house to admire it. More thorough clean up, using magnetic tools to discover razors, nails and staples from tearoff. Better, more complete tarping to catch debris, not only on the slant side of the roof, but also the gable sides that are not slanted. They were not tarped, and that is where most of the debris and nails were found. An assessment for lead paint BEFORE working, which was promised, but not done. A smaller Interlock sign, in less garish (ie not fluorescent) colors, to display that would be acceptable for Washington County and the laws of other areas. I am not sure if the cardboard, water bottles and metal was separated and recycled off site, because it was all tossed into the same dumpster, but I would hope that since Interlock prides itself on eco-friendly recyclable materials, that it would follow through with recycling paper and metal as well. Roof, material, workmanship: 5 stars, Areas for improvement: Testing for lead pre-install, Tarping for Debris catch and Cleanup: Improvement needed, Communication re: Cleanup: Improvement needed, Information re: payment (cash, no credit card, upon completion): Improvement needed

★★★★★
Review: November 26, 2018Completion: November 26, 2018

We are very pleased with our new Interlock roof. While our house is nearly 100 years old, the new roof fits perfectly with the style and enhances the look of our home. We began receiving compliments from our neighbors almost immediately. Michael Laduke and his crew were professional and courteous, keeping the surrounding yard clean of debris and closing the gates each day to prevent our dog from escaping. Although the crew was slightly delayed due to an unfortunate encounter with a deer on the road, the work was completed just before the Thanksgiving holiday, adding the health and well-being of the crew and the beauty and protection of a new roof to our list of things to be thankful for. We greatly appreciate Mr. Laduke’s commitment to detail and his personal assurance that the project was completed before the holiday weekend. We would most certainly recommend Interlock Roofing Systems to anyone considering roof replacement.

★★★★★
Review: October 15, 2021Completion: August 19, 2021

Interlock Roofing installed an excellent metal roof on our house. It looks amazing and will last for years! The installer, Victor, was very professional and did a great job. He explained the work being done and even replaced a worn board on the garage. This product is definitely worth every penny! Positive Responsiveness, Punctuality, Quality, Professionalism, Value Services Attic venting, Roof inspection, Roof installation

★★★★★
Review: June 15, 2023Completion: February 28, 2023

Beautiful roof, replaced 44-year-old concrete tile. Installers showed up when scheduled, were conscientious and knowledgeable. They were hardworking, even in difficult cold weather. Communication was challenging while waiting our turn, but this was addressed. Ten stars for all of you!PositiveResponsiveness, Punctuality, Quality, Professionalism, ValueServicesRoof installation

★★★★★
Review: December 15, 2021Completion: February 17, 2004

Interlock Roofing installed a metal roof on our family home and it looks amazing. It has held up to extremely high rainfall so far. The crew that installed my roof was very professional and polite. I would recommend Interlock Roofing if you are in the market for a new roof.PositiveResponsiveness, Punctuality, Quality, Professionalism

★★★★★
Review: July 15, 2021Completion: October 19, 2020

It has now been nearly six months since our Interlock roof installation, and we couldn't be happier with it. We debated getting a metal roof due to the greater upfront costs relative to a standard composite roof, but we're not planning on going anywhere anytime soon, so the peace-of-mind of a lifetime roof -- knowing we won't have to do this again, and that the company stands behind the product the way they do -- makes it worthwhile. The installation crew was professional, and their customer service has been responsive when needed. Neighbors have commented too on how good our roof looks! Recommended! Positive Responsiveness, Quality, Professionalism Services Roof installation

★★★★★
Review: September 15, 2020

At the recommendation of a neighbor, we chose Interlock Roofing and we couldn’t be happier. We’ve been homeowners for 40+ years and fortunately have never had to worry about a roof, as our houses were new, and we moved somewhat frequently. Then two years ago we bought a second home on the Oregon Coast and knew we would have to replace the roof within a few years. Until finding out about Interlock, I fretted about having it replaced. So, after having our second home’s roof replaced, I asked Damon to inspect our main, 16-year old house in Portland. He thought it had anywhere from 2 to 5 years life in it, but we opted to have it replaced for three reasons. First, why wait for a leak, second, because the warranty is going to outlive me and finally…it will never be cheaper. The roof is absolutely beautiful and is the envy of the neighborhood. Dealing with Interlock has been such a pleasure on ALL fronts. The communication throughout the process was flawless. They did everything and more that was promised. Very few products and services have ever impressed me more. ">" alt="Interlock Aluminum Shake Roof - Portland, Oregon USA" width="1500" height="1124" />

★★★★★
Review: October 16, 2015Completion: September 29, 2015

We are thrilled with the quality and look of the roof! The installers are true craftsmen of their trade and were so polite and courteous. Nothing negative to say. The sales rep that came to our home was sure a top notch sales rep for your company. Mike Rasmussen was very impressive with his knowledge and ability to make you understand. We had four estimates prior to Interlock roofing and had pretty much made a decision prior to Mike coming to our home. I was going to cancel the appoitment with Mike but felt it would be rude to do so on the same day so we kept the appoitment. So glad we did !!! Mike did an amazing job at showing all the advantages of Interlock roofing compared to ordinary roofing. Best decision we could have made for our home and ourselves! Now comes the only part we were not pleased with and feel you could greatly improve. We were promised a start date of absolutely no later then Sept. 14th. No materials had been delivered or no communication from Interlock had occured and it was Sept. 12th. I made a phone call and was informed the roofing material had not been delivered yet and the new start date would be Sept. 21st. Why we had not been kept in the loop on that I am not sure. The morning of the 21st I receive a phone call from Roland Stark saying an employee called in sick and they would be starting the next day on Tuesday the 22nd. Tuesday the 22nd I receive a phone call from Roland Stark that the employee called in sick again and they will begin the next day Wed. the 23rd. I questioned why you could not begin the tear off without him and was told he was the lead guy. During the sales process we were informed that all of your installers have been with you for many years. I believe Mike said at least 14 years. But I could be wrong on that. Maybe he said 13 years. I was confused why tear off could not begin with that kind of experience. Roland said at the latest they would start Friday and his crew promised they would work Sat. and Sunday both to complete the job. We were promised job completion Sunday the 27th at the latest. Sat. the 26th is the actual day the men showed up to begin on the roof. The men showed up prompt and begun work immediately. Very professional and hard working. I was impressed. As they wrapped up for the evening to leave I said, " See you tomorrow." They looked a little confused and replied, " We will be back on Monday as we have worked all week and are going home to see our wives and kids." Completely understandable except Roland told us they had been home sick all week. Official finish date was Sept. 30th. Roland needs to be more honest and upfront about the scheduling. It was very frustrating and was the only negative thing about the whole experience. We had Leaf Filter gutters and also Lifetime Exteriors(new siding) both scheduled to begin work the day following the roof project. Each time Roland promised a new date these two businesses had to be contacted and they would re-schedule their crews. Very frustrating for both us and them.You requested where Interlock could have improved, therefore I gave you an honest answer. But I am keeping that between your company and us. The negative scheduling part that is. When asked how we like our new roof we respond with," Best decision we ever made for our home. We love it and could not be happier!!!! If we had it to do over again we would certainly choose Interlock Roofing." Have NO REGRETS. LOVE the roof.

★★★★★
Review: April 20, 2026Completion: June 20, 2019

We’ve had our roof for about 7 years and have been very pleased with it. Recently, I scheduled gutter cleaning which was complicated by a run of wet weather which makes the roof very slippery. The gutter contractor asked if we had ever considered installing safety anchors. I didn’t know there was such a thing. I called Interlock and Ivan came by to take a look. He quickly determined appropriate locations for the anchors that the gutter cleaners could clip their safety harnesses to and showed me an example of the anchor itself. He also offered to paint them black to make them more inconspicuous on our dark roof. He returned about a week later for the install and afterwards showed us pictures of the anchors from the roof and pointed them out from the ground. Overall very professional, prompt, excellent service.

★★★★★
Review: May 8, 2025Completion: April 17, 2025

We love our roof! Interlock was wonderful to work with. Very knowledgable and helpful throughout the whole process. The team that installed were amazing and did amazing work. They cleaned up everything in a timely manner. One feedback I would have is giving more updates on when the project was slated to be started, originally was schedule during our vacation and we didn't know til a few days before we left. Overall we are very please and cant wait to never change our roof again!

Read all Oregon metal roofing reviews →

Nearby service areas in Multnomah County

Interlock® metal roofing is also installed in these communities near Markham:

Interlock Metal Roofing (PNW) Inc. also services nearby States

Beyond Markham, our team installs Interlock® metal roofing across:

Metal Roofing FAQs for Homeowners in Markham

The following metal roofing FAQs are designed specifically for homeowners in Markham, Oregon. Whether you are building a new home or replacing an existing roof, understanding how roofing materials perform in local weather conditions is essential. From wind and storm protection to fire resistance, hail impact, snow loads, and coastal moisture exposure, Interlock’s Lifetime Aluminum Roofing System is engineered to provide long-term durability, energy efficiency, and peace of mind in Markham.

Does a metal roof handle Markham's snow and ice buildup?

Yes—metal roofs shed snow and ice far more effectively than asphalt, which is critical in Markham's climate of about 48 cm annual snowfall and 36 freeze-thaw days per year. The smooth, hard surface of Interlock's four-way interlocking aluminum panels prevents water from pooling and refreezing into ice dams. Snow slides cleanly off the steep panels rather than sitting and melting unevenly. Optional snow guards let you control where snow exits. The lightweight design (Slate at 0.41 lb/sq ft) means no structural concern even if snow does accumulate briefly.

Why won't my aluminum metal roof rust like steel ones do?

Aluminum cannot rust because it contains no iron—the metal that oxidizes and degrades. Instead, aluminum develops a thin, invisible oxide layer that actually protects the underlying metal. If that layer is scratched, it self-heals chemically. Interlock's 3105-H24 and 3003-H24 aluminum alloy (ASTM B209 certified) is roofing-grade specifically for this durability. Add the Alunar 70% PVDF fluorocarbon finish applied to both sides of every panel, warranted 30 years against fading, and you have genuine corrosion immunity—especially valuable in Markham's 1,468 mm annual rain, which would accelerate steel corrosion.

Can a metal roof handle Markham's wind gusts?

Absolutely. Markham's typical gusts reach 116 km/h, and Interlock metal roofing is warranted to resist wind speeds up to 120 mph (193 km/h)—exceeding your local weather by a comfortable margin. The four-way interlocking aluminum panels lock together so tightly that wind cannot separate or lift them. The system is engineered to distribute uplift pressure across the entire panel grid rather than concentrating stress at fasteners. Even in severe Pacific Northwest storms, that mechanical interlock design has proven itself since 1998, from coastal salt-air homes to Antarctic research stations.

Will I need to reinforce my roof structure for a metal roof?

No structural reinforcement is needed. Interlock's aluminum panels are extraordinarily light—the Mediterranean Tile profile weighs about 0.59 lb/sq ft, roughly 96% lighter than concrete or clay tile. This featherweight design means you can install metal roofing directly over most existing roofs, saving thousands on structural work and disposal. Your home's framing already supports asphalt shingles plus snow (Markham averages 48 cm annually), so aluminum panels—which weigh less than a single layer of asphalt—pose no structural demand. Many homeowners save installation time and cost by going directly over their old roof.

Does hail damage cost me money on a metal roof?

Metal roofs are actually hail-resistant and may lower your insurance premium. Interlock achieves UL 2218 Class 4 impact rating—the highest available—and the Guardian warranty even covers perforation from hailstones up to 1.5 inches. Many insurers recognize this durability and offer discounts. Compare this to asphalt shingles, which can be damaged by small hail; homeowners often file claims for costly repairs or replacement. While Markham's 10-year climate data show no extreme hail history, the hail resistance means you're protected and potentially rewarded by your insurer instead of penalized.

What warranty comes with Interlock metal roofing, and how long will it really last?

The Guardian Warranty is a lifetime limited, non-prorated material warranty for the original owner, covering rust, rot, splitting, cracking, curling, and loss of impact resistance—problems that plague asphalt and wood. It's also one-time transferable, giving the next owner 50 years of coverage from completion. This means your roof is guaranteed for your ownership and adds resale appeal because the buyer inherits decades of protection. In Markham's freeze-thaw cycle (36 days per year), asphalt becomes brittle and shingles curl; aluminum simply doesn't. Real-world Interlock roofs installed since 1998 have proven 25+ year performance across harsh coastal and northern climates.

Does a metal roof save money on cooling in summer?

Yes, if you choose an energy-efficient color. Interlock offers energy-efficient finishes with thermal emissivity of 0.84 and initial solar reflectance up to 0.55 (example: Aged Copper Penny), meaning they reflect heat that dark asphalt absorbs. In Markham's 2,957 annual sunshine hours, that reflection adds up to measurable cooling savings, especially on south-facing slopes. The Cool Roof Rating Council rates these colors independently. While Markham's mean temperature of 11.5°C is cool, the extended daylight in spring and summer reduces indoor heat gain when it matters. Over a roof's 50+ year life, energy savings compound significantly compared to asphalt.

How much maintenance does a metal roof need versus asphalt or tile?

Metal roofs need almost none. Asphalt shingles require periodic inspection for curling, cracking, and moss growth; wood shakes must be treated to prevent rot and insect damage; clay tile requires regrouting and replacement of broken pieces. Interlock aluminum simply doesn't degrade—it won't rot, split, or curl. Markham's 1,468 mm annual rain means moss can grow on any surface, but a quick rinse removes it; the Alunar 70% PVDF coating resists algae adhesion better than porous materials. The CALGreen-verified design acknowledges reduced maintenance demand. Many owners report that a gutter cleaning twice yearly is all they do.

Is metal roofing Class A fire-rated?

Yes. Interlock aluminum roofing achieves Class A fire classification because aluminum is non-combustible—it cannot ignite or spread flame. This meets the highest fire safety standard in building codes. The ICC-ES evaluation report ESR-1790 (IBC/IRC, reissued 2025) confirms compliance. For homeowners in wildland-urban interface areas or those seeking maximum fire safety, Class A non-combustible metal roofing is the gold standard. While Markham's 10-year data don't indicate extreme wildfire risk, Class A rating also reduces fire insurance costs and provides peace of mind. Asphalt shingles, by contrast, are Class C or lower and can ignite or spread flames.

Can you install metal roofing over my existing roof, and how long does it take?

Yes, most Interlock installations go directly over the existing roof—no tearoff, no landfill hauling. The lightweight design (0.41–0.59 lb/sq ft depending on profile) means no structural reinforcement is necessary. Installation timeline depends on roof size and profile, but the metal-to-metal interlock system installs faster than asphalt nail-by-nail work because panels lock together mechanically. Local installer Interlock Metal Roofing (PNW) Inc. has served the region since 1997 and handles all logistics. Going over an existing roof saves thousands in labor and disposal costs—money you can redirect toward better materials or other home improvements. Ask your installer for a detailed timeline during the estimate.

Is a metal roof a good choice for Markham’s climate?

Yes. Markham averages about 48 cm of snow, 1468 mm of rain, roughly 36 freeze–thaw days a year, with peak wind gusts near 116 km/h. Interlock® aluminum roofing is wind-rated to 193+ km/h (120 mph), UL 2218 Class 4 impact-rated and Class A fire-rated, and its four-way interlocking panels shed snow and resist ice dams and freeze–thaw cracking — all backed by a lifetime limited, transferable warranty.

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