Commercial Metal Roofing

What Metal Roof Installation Do You Have?

While your commercial building’s flat or low-slope roof can be made from a wide variety of materials, metal roofing is a popular option on buildings like the large warehouses and manufacturing facilities common in our eastern Pennsylvania service area here at Unlimited Commercial Roofing.

But, what kind of metal roofing does your building have? Is it painted or coated? The unique properties of your commercial metal roof—including certain factors about its construction—affect how maintenance and repairs should be approached. And you probably have unanswered questions about metal roofing’s performance and longevity, especially if you’re new to commercial building ownership or management.

The good news is that most metal roof types are great candidates for metal roof restoration, so if you’re experiencing age-related problems like rust, damaged fasteners, and weak spots, you likely don’t need to take on a costly replacement project.

Today’s post gives you a little more information about each of some typical commercial metal roofing types, including what you need to be on the lookout for in terms of issues.

Top 3 Most Common Commercial Metal Roof Materials

While there are many different types of metal and alloys available for roofing, there are really only three that are installed on standard commercial buildings today: aluminum, steel (in a few different formats), and zinc. Each is strong, durable, and brings many benefits to your building, though the cost for new installations can vary wildly by material. (Note that copper is also a popular metal roof option, but tends to be installed on buildings with more architectural or historical value than most hardworking commercial buildings because it’s expensive.) Let’s take a closer look.


Did you know that aluminum is the third most abundant metal on Earth? The fact that it’s so readily available makes it a cost-effective material for roofing, as well as so many other familiar applications. And it offers a long list of “pros” for your commercial building, too, including its unique ability to stand up to salt-heavy air and precipitation in coastal environments.

If you have an aluminum roof today, these are the benefits you’re getting:

  • High strength without heavy weight – roof systems that weigh a lot can put unnecessary stress on the structure of a building. Aluminum is an amazing material because it stands up to harsh weather as well as (or better than) much thicker materials.
  • Excellent corrosion resistance – aluminum does not rust in the traditional sense. When installed properly, it will give you many years of reliable service without breaking down or corroding as some other metals do.
  • Environmentally friendly material choice –most newer aluminum roofs contain about 95% recycled content, and the material can be recycled again at the end of its lifespan. When covered with a reflective coating, aluminum can also keep your roof’s temperature lower, which saves big on your building’s energy usage.

Issues to watch out for

While extremely durable against the elements, as we mentioned, aluminum roofing is prone to denting if debris—like falling tree limbs—strikes it.

Additionally, aluminum expands and contracts with air temperature changes, which means it must be installed properly to assure that fasteners don’t prematurely fail. This movement can also cause loud noises at various times of day and as the seasons change.

Similarly, the noise that raindrops create when hitting aluminum roofs can be troublesome to certain types of businesses. You’ll need to consider other roofing types if your work demands a predictably quiet environment (such as video production or audio recording) or invest in soundproofing.


Steel roofing comes in a few different formats to provide distinct advantages. The most common steel roofs are galvanized, Galvalume-coated, and stainless steel materials.

Galvanized steel roofing

To galvanize steel is to coat it with other metals—namely zinc—to make it resistant to corrosion in applications where it will be exposed to the elements. This process produces a material that’s nearly as durable as stainless steel, which we’ll highlight in a minute, but that’s much lower cost. It’s extremely strong like aluminum, but less prone to denting and expansion/contraction from temperature changes.

Galvalume® steel roofing

Galvalume is a brand name of the Bethlehem Steel (now U.S. Steel) company, which refers to a specific coating process that allows a carbon steel sheet material to wear better over time by introducing additional metals and elements to it than simple galvanizing does. Per U.S. Steel’s website, “The nominal coating composition is 55% aluminum and 45% zinc. A small but important addition of silicon is included in the coating alloy.”

The biggest benefits of Galvalume are the color options available and the fact that it tends to be the least expensive metal roofing option. Galvalume is long-lasting. It is also easy to install and can sometimes be re-roofed over an existing roof made of other materials. (It’s also a great candidate for our restoration process!)

Stainless steel roofing

Stainless steel roofing is excellent in environments with extreme weather conditions, and it doesn’t expand and contract very much with temperature changes. While it’s not quite as able to withstand salt air and spray as aluminum in coastal settings, stainless steel roofs are becoming more common in almost all climates and environments since the material’s longevity is nearly unbeatable—it’s corrosion-resistant for possibly up to 60 years!

Issues to watch out for

Steel roofing isn’t easily dented like aluminum roofing, and it weathers well across the board. There are also a lot of options to choose from with steel—from low-cost Galvalume to more premium stainless. The most significant issues your steel roof may face are standing water due to low spots developing, which can cause leaks to form along panel seams.

Additionally, Galvalume can fade and “chalk” (a term for the development of a white residue that forms over time on the roofing surface) or corrode in places where it contacts other materials including concrete, brick, other metals, and treated lumber.


As we’ve discussed, zinc is an essential component in the galvanization process to make steel corrosion-resistant. Indeed, this metal has incredible longevity because it doesn’t break down easily—there are zinc roofs in existence today that have been in place for 100+ years! Zinc is naturally reflective whether coated or uncoated, and it’s actually self-healing, which means small dents and scratches to the material’s surface will improve with time instead of getting worse.

So, why not install a zinc roof? The main answer is cost. Recent industry data suggests it generally costs about $600-$900 per roofing panel or square. That’s simply cost-prohibitive for most commercial buildings. In fact, we’ve mainly only included it here to show how its impressive qualities can be gained by installing galvanized steel roofing.

Issues to watch out for

If you do happen to have a zinc roof, you have a major asset, but it’s also a little tricky. Because the metal lasts so long, you’ll actually need to consider that your roof deck may be damaged or rot from improper ventilation in the system. So, while the roofing material itself may not fail, its substructure could cause it to need premature replacement.

Is Your Metal Roof Leaking? It’s Time to Take Action…

No matter what type of metal roof you have on your commercial building, if you’ve got leaks, it is imperative that you schedule an inspection by a professional roofer right away.

Ideally, your building’s roof should be inspected at least annually regardless of its age. If you experienced damage from strong storms this past summer, however, it’s even more important to have a professional determine whether repair or restoration could be needed sooner than you may have expected.

Unlimited Commercial Roofing offers guaranteed restoration systems from Conklin that provide robust and leak-free performance backed by industry-leading warranties. In fact, metal roof restoration may make your commercial building’s roofing able to work harder for you than when it was brand new, thanks to energy-saving reflective coatings!

Contact us now to schedule your free inspection and learn more about how Unlimited Commercial Roofing can turn your metal roof’s weak points into strengths!