5 Types of Metal Roofing Materials
1. Copper — Extremely long-lasting, very soft with low melting temperature
2. Aluminum — Long-lasting, resistant to salt water corrosion
3. Zinc — Extremely long-lasting, resistant to corrosion and lowest melting point
4. Steel — Three variations: galvanized, galvalume, and weathering steel (Corten)
5. Tin — Often referring to steel, used prior to World War II. No longer commonly applied.
Metal roofing has often been called the “Cadillac of Roofing.” Depending on your opinion of that particular manufacturer, this comparison could be less than flattering. In reality, a metal roof doesn’t describe a specific product, rather an entire range of products. The term itself does not even explain whether you are speaking about a steel, aluminum, zinc, or copper roof. Given metal roofing’s reputation for being able to handle a huge range of requirements and design options, a better comparison might be that metal roofing is the “Sport Utility Vehicle of Roofing.”
In this article, we will break down the differences in metal roofing material options, and the pros and cons of each material, profile, and source.
Types of Metal Roofing Materials
When you hear the phrase “metal roof,” your thoughts likely go towards a steel roof, but the term encompasses a much larger variety of materials. Depending on your location and environment, the type of material will be a crucial first step in deciding which direction to go. While an aluminum roof is an excellent option for resisting rust in salty regions, it’s durability factor can be much lower than other materials. Steel, Copper, and Zinc metal roofing materials also have their own pros and cons.
Copper Roofing – Pros & Cons
Considered to be the grandfather of metal roofing, copper roofing has been used for centuries around the world. Copper is an extremely long-lasting metal that in ideal environments, can last well over 200+ years. Copper roofs are 100% recyclable too, making them wonderful green roof options.
Copper is an extremely soft metal, which makes it among the quietest types of metal roofing. However, with modern installation practices, all metal roofing now recommends proper substrates and insulation that minimize noise from rain or hail at the same level. The softer nature of Copper Roofing also means that in hail prone regions, it may be easily damaged. As a softer metal, hailstones will easily dent the Copper. While this lowers the aesthetic value, it also performs better than a harder metal that, with a large enough hailstone, will puncture rather than simply dent the roof.
If metal roofs are the SUVs of roofing, Copper roofs are the Range Rovers of their class. This brings up an apparent downside to Copper. Like the Range Rover, it is extremely expensive and depending on your needs, may be more than you need to get the job done. Another negative aspect of Copper is its tendency to expand and contract with swings in temperatures. While this can be controlled with the proper panel or shingle, it does need to carefully be considered when choosing this metal.
Aluminum Roofing – Pros & Cons
If Copper is the Range Rover of roofing, then Aluminum is easily considered to be the Dune Buggy of roofing. Stay with us here. Take a Volkswagen Beetle, pull off the doors, the roof, and all unneeded features. Seal off the essentials to prevent salt spray, add a roll cage, and upgrade the suspension. Throw some nice sand tires on the thing and take it for a cruise along the beach… you now have the vehicle that best describes the strength and corrosive durability of an Aluminum roof.
Aluminum metal roofs are often highly recommended for use in coastal climates. This is mainly due to aluminum’s resistance to salt corrosion compared to other types of metal roofing materials. While the common perception of Aluminum is that it's not effected by corrosion, the reality is that it's a highly active metal and almost instantly reacts to atmospheric conditions.
This rapid reaction is actually what protects it so well. The outer layer of aluminum reacts with the oxygen in the environment, creating a layer of aluminum oxide, which effectively seals the inner layers of the metal from any future corrosion. This process is similar to an A606 Weathering Steel process, but in a much faster time frame and with longer lasting protection. Aluminum is often used with a painted coating as it’s natural patina over time is not typically thought of as aesthetically appealing.
Like Copper, Aluminum’s downside often comes down to cost. While it can offer a better protection against corrosion, it's also more expensive than comparable solutions that use aluminum as a coating. As a commodity, Aluminum’s price range fluctuates depending on the market. Typically, the price for this metal lies somewhere in the middle between steel and copper. Due to its price, Aluminum is often used in much thinner thicknesses than steel.
While Aluminum’s strength-to-weight ratio is higher than steel, the factor of cost often results in panels that are too thin for their surroundings. In regions with high winds, hail, or strong environmental stresses, this can result in damage to the roofing material. Properly identifying the environmental strains that your Aluminum roof will face will be crucial in choosing the right design.
Zinc Roofing – Pros & Cons
Who remembers the original Humvee? An extremely durable and dependable machine that could take you anywhere you needed to go, yet at a pretty price. This is Zinc in a nutshell.
Zinc is an amazing metal, able to use its patina to heal scratches over time, plus stay strong for over 100 years. The natural properties of Zinc make it a favorite for commercial projects due to its ability to be easily formed and manipulated into amazing shapes. While the chalking of Zinc over time is not considered an appealing aspect of the metal, it can be cleaned and controlled to an extent.
While the Humvee was not exactly a “green vehicle,” Zinc could be considered one of the greenest metals available for roofing. Zinc has a lower melting point than other roofing metals. This lower melting point means that processing the Zinc for use as a building material requires up to a ¼ of the energy that it takes to process steel or copper. Zinc is also 100% recyclable and available in most local markets, making it an extremely green material, even compared to Copper or Steel.
The main downside to Zinc is the chalking effect from an aesthetic point of view, and the price. Zinc is not cheap. In fact, Zinc often is comparable to Copper. Like Copper, Zinc also requires expert installation to properly make use of its advantages as a building material.
Zinc, like most bare metals, does patina into a blue/grey appearance if left unpainted. Along areas where water flows, this often leaves a chalk residue that many find unappealing. Zinc is also a very soft metal, and can be easily damaged by hail or high winds depending on the panel or shingle design.
Steel Roofing – Pros & Cons
Steel is an alloy, made from iron and other elements. Used in every aspect of building, steel roofing has often been one of the most common materials found on a commercial construction site, and is now often incorporated into residential builds. While the initial creation of steel can be an energy-intensive process compared to a metal like Zinc, the recyclability and availability of the metal alloy means that most of the steel we use today is made from recycled material rather than new. In fact, steel is the most recycled material on the planet, making it an incredibly green building material to work with.
When compared to other metals, steel is also the least expensive. While also being a commodity, steel is often priced at a much lower rate than Aluminum, Zinc, or Copper. This makes steel both affordable and available at a greater amount compared to the other metals on this list.
There are three primary Steel Roof types: Galvanized, Galvalume, and Weathering Steel.
- Galvanized Steel is actually created by using a layer of Zinc to protect an inner layer of steel from corrosion. This coating helps extends the life of a steel panel and slow the corrosion process. Galvanized Steel is the most common form of Steel Roofing material.
- Galvalume Steel is similar to Galvanized, but rather than using a primarily Zinc coating, Galvalume uses a combination of Aluminum and Zinc. The Aluminum better protects against corrosion in certain environments compared to Galvanized, and also provides a smaller, smoother spangle for a more uniformed appearance. Due to its Aluminum qualities, Galvalume offers better surface protection than Galvanized, but is vulnerable to scratches or cut edges.
- Weathering Steel is a form of steel that was originally designed for use in heavy steel industries like bridge construction. An outer layer of steel is designed to intentionally rust, protecting the inner layer of steel. In effect, Weathering steel roofing works similarly to Aluminum in the patina process, although unlike Aluminum, this process takes a longer period of time. It's important to remember that Weathering Steel does intentionally rust, and is not designed to be used as a structural solution for steel roofing. It is often used in accent roofs, or with the expressed understanding of the rusting process and the need for regular maintenance.
Steel Roofing has made huge advancements in the past 50 years and can now be used to mimic Copper, Zinc, and other more expensive metal roofing materials. This is done through paint systems that create a painted solution to match the natural patina of a Copper, Zinc, or even the Weathered Steel look. These solutions often carry long warranties and make ideal choices for remodels, restorations, and new builds.
Steel’s primary advantage over other materials in this list is it’s flexibility of use and cost. Because of the higher prices of other metals, Steel has been the primary solution for both commercial and residential projects, and that trend looks like it will continue in the future.
As a green solution, it is both easily accessible and highly recyclable. As options go, because it is among the hardest metal options, it can be used in most weather environments, and works well in hail and high winds. It's a common sight in mountain regions with high snow volumes, and is a preferred solution in regions prone to hail.
Steel is a highly flexible option both commercially and as a residential metal roofing option. For its diverse range of uses, its availability and cost, and the durability it provides, Steel is the Jeep Wrangler of roofing options.
Tin Roofing – Pros & Cons
Tin Roofing is an often-requested item by enthusiasts around the United States and Canada. The term is used interchangeably with metal roofing, steel roofing, or galvanized steel. In fact, Tin is an incredibly rare, and unused metal for roofing. Tin itself is an element, like Copper or Zinc. Tin was introduced as a canning material, which was then adapted by rural DIYers by flattening out the material and using it as a shingle when other materials were not available.
When Aluminum became the standard for containers, which replaced Tin, so went the use of it as a DIY building material. In reality, when you hear reference of a tin roof, in modern times this is normally referring to either a galvanized steel or aluminum material.
For its DIY use in the 19th century, and its ability to remain a part of our vernacular long after it left, Tin could be fondly considered the Willy’s Jeep of roofing. While it still has many uses in science and technology, Tin is no longer generally used as a building material option.
While each of the five types of metal roofing materials have their advantages, in the end, the choice often comes down to cost. Copper can be aesthetically the most appealing of the metals, but also the most expensive. Zinc is the greenest of the materials due to its low melting point, but is also very expensive. Aluminum offers a great solution in coastal regions, and is less expensive than Copper or Zinc. Steel is the most used of the materials, making it less expensive and affordable as a metal roofing option for homeowners as well as commercial builds. Tin had its day, but now often refers to galvanized steel when spoken about in terms of roofing.
Each of these metals has their advantages and weak points. Choosing the right metal to use for roofing comes down to the installer you choose, the location of your build, and the stresses and strains it will be put through. Make sure to always hire experienced roofing contractors who not only have worked with metal roofing, but the specific metal you choose to use on your next project.