Whether you’re in the market to purchase a new metal roof, a distributor trying to sell metal coils or sheets to customers, or a contractor dealing directly with a home or business owner, it’s vital to know the pros and cons of different metal roofing materials.
Three of the most common materials used in metal roofing are Galvalume, zinc, aluminum. Luckily, there isn’t just one solution for every single customer, so the advantages and disadvantages of each metal should be discussed in depth with the contractor, distributor, architect, or manufacturer before making a final decision.
As one of the leading distributors of coated and bare metal products in the industry, VITINA ROOF helps individuals find the solution that will work best for their specific residence, building or business every day.
Galvalume roofing material combines three of the most important metals used in roofing today—steel, aluminum, and zinc. Manufacturers begin with a carbon steel base sheet, which is then continuously hot-dipped with aluminum and zinc alloys until it reaches a coating consisting of 55% aluminum, 43.4% zinc, and 1.6% silicone over the base metal to protect it from the elements. This system allows for one material to have some of the best characteristics of each included metal—making it one of the fastest growing materials in today’s metal roofing market.
Pros of Galvalume Roofing
- Color Options – One of the most appealing aspects of Galvalume roofing, especially for homeowners, is the fact that Galvalume can come in an array of different colors. These pre-painted options allow for more versatility when buyers are trying to match the roofing to their home or business.
- Least Expensive – Compared to other high-quality metal roofing materials, Galvalume costs the least amount of money. Depending upon the thickness, color, and quality of the desired Galvalume panels, pricing could range anywhere from $75 to $250 per roofing square (100 square feet).
- Corrosion Resistant – Galvalume is designed to combine the toughness and strength of zinc with the rust-resistance of aluminum. Testing in the field indicates that Galvalume roofing could last as long as 60 years without any extreme signs of corrosion.
- Easy to Form – Galvalume is an ideal material for rollforming and panel forming, making it easy for contractors to make any profile for any project.
- Recyclable – Galvalume is 100% recyclable, meaning that any scrap metal left over from a job or old metal roofing that has been replaced can be easily recycled.
- Installed Over Existing Roof – One of the major benefits to choosing Galvalume is the fact that it can be retrofitted or re-roofed over an existing roof, meaning no tear-off cost is required. Good contractors are trained on this procedure, so make sure to find one who knows how to cover an old roof if desired. A homeowner can also elect for Galvalume to be used as a completely new roof as well.
Cons of Galvalume Roofing
- Oil Canning – Oil canning is an inherent characteristic of light-gauge, cold-formed metal products, especially products with broad flat areas. It is a visual phenomenon seen as waviness or distortion in the flat surfaces of metal wall and roofing products. Oil canning is subjective and normally only an aesthetic concern that does not affect a product’s strength or performance. This occurrence is a possibility for any kind of metal roofing or walls, including Galvalume. But there are methods to minimize the appearance of oil canning, including: 1-Hiring an experienced contractor who knows the best methods to reduce oil canning, including: Panel thickness , Appropriate space between panels, Underlayment, Deck or other supporting structure is in alignment. 2-Buying trustworthy brands of coil 3-Using striations or bead stiffeners in the flat area of the panel to minimize the appearance of oil canning.
- Fading/Chalking – One drawback to painted Galvalume is the fact that the color will fade over time due to sun and UV exposure. There are ways to slow down this process, most of which depend on the resin or paint coating used on the metal. Kynar painted systems have the most fade-resistant coatings, followed by silicone-modified polyester (SMP) and polyester systems. Also, painted Galvalume could be susceptible to chalking, a whitish residue visible where the coating is present. Again, it’s important to pick the coil with a tested and proven chalk rating.
- Interactions with Other Materials – Galvalume performs best when not in contact with other materials, such as iron, copper, concrete, bricking, and treated lumber (decks). Contact with or galvanic reactions to these substances could result in quicker corrosion or complete failure of the Galvalume roof panels.
For residential homeowners and business owners looking for a metal roofing material made to stand the test of time, zinc is always a great option. Among contractors and architects, zinc’s popularity in metal roofing projects has experienced a steady increase in the world because of its ease of use, immunity to corrosion, and other sustainable features.
Pros of Zinc Roofing
- Longevity – Zinc roofs have been known to last anywhere from 60 to 100 years. Studies have shown that in some cases zinc roofing could last up to 150 years depending upon the quality of installation, building properties, and climate.
- Ecofriendly – Since zinc is a natural metal extracted from the ground, zinc’s toxicity levels are very low, even after fabrication. Homeowners and business owners do not have to worry about any toxic run-off or ground pollution surrounding their zinc roofing. Additionally, zinc is a non-ferrous metal, meaning it does not contain iron, and therefore requires less energy to manufacture.
- Energy Savings – Metal roofing in general cuts down on the cost of heating and cooling because it reflects the sun’s heat that is normally absorbed by asphalt shingles, tiles, etc. Using coated or uncoated zinc roofing material helps reduce the amount of energy absorbed into a home or building.
- Self-healing – Zinc actually possesses its own outer protective layer, which prevents against corrosion, scratching, and panel markings. If wind or another element were to scratch the surface of the zinc roof, the metal’s protective layer would actually fix and correct itself over time.
- Easy Maintenance – Zinc’s self-healing properties often means the building owner doesn’t have to perform any routine maintenance to the roof. It’s often said that zinc roofing is the “install and forget about it” option to metal roofing.
- Easy to Form – Architects and contractors often use zinc in their projects because it’s a softer metal and can be easily shaped into different profiles for rollforming, gutter forming, and seam creation.
Cons of Zinc Roofing
- Expensive – The most prominent drawback to zinc roofing is the price. While there are many variables that factor into determining the price, zinc roofing can cost anywhere from $600 to $900 per roofing square. When selecting the best roofing, keep in mind that metal roofing lasts decades longer than asphalt roofing and requires less maintenance and replacement.
- Oil Canning – Like any metal roofing, zinc metal roofing could be subject to oil canning.
- Underside Corrosion – If the zinc roofing is improperly coated on the underside of the panel, corrosion could take place. This occurs when water molecules get trapped underneath between the panel and the insulation or underlayment, which can cause the metal to weaken if not coated.
- Ventilation – All zinc applications require adequate ventilation to help the system from failing from the inside (or underside) out. Above deck ventilation products, such as Sharkskin Ventilated Mat or Enkamat, combined with using the appropriate details will contribute to the longevity of a zinc system. The correct ventilation process for zinc roofing is more of a precaution than a disadvantage.
Aluminum is one of the most predominant and popular metals in the world, mainly because of its use in the canned beverage industry. But aluminum, the third most abundant metal on Earth, spans way beyond this scope and makes a great material for the metal roofing industry, especially for projects in sea and saltwater environments. Not only does aluminum stand up to extremely harsh weather conditions, but it’s one of the most sustainable metals in the world, which is why it’s become such a popular roofing choice for structures.
Pros of Aluminum Roofing
- Highly Recyclable – Nearly all metal roofing is recyclable in one way or another. The best part about aluminum is the fact that about 95% of all aluminum roofing installed across the world is made from recycled aluminum materials. Sustainability in construction has become vitally important in the past 20 to 25 years, which is why the use of aluminum roofing is becoming more common.
- Lightweight Strength – Aluminum sheet metal is very lightweight and easy for a contractor to form and install. Even though aluminum is a thinner and lighter material, it’s still very durable and can replicate the strength of much thicker metals.
- No Rusting/Corroding – One of the biggest selling points of an aluminum roof is the fact that it doesn’t have red rust and corrosion is generally minimal as it ages. Studies have even shown that aluminum can work great in coastal areas with high rainfall and seawater spray conditions. Aluminum performs better in coastal environments than Galvalume or other steel materials.
- Medium Price Point – Aluminum is in the middle range when it comes to material cost, making it more affordable and realistic for some home and business owners. Aluminum is cheaper than both zinc and copper with a price point of about $200 to $575 per roofing square depending on thickness, finish, and panel type.
- Readily Available – As mentioned before, aluminum is the third most abundant element in the Earth’s crust, making it an ideal material for structural applications. Unlike a more restricted material such as copper, it’s not difficult to come by aluminum roofing and contractors who know how to install it.
Cons of Aluminum Roofing
- Natural Color – Using aluminum roofing in its natural color (silver/gray) isn’t recommended by too many architects and installers. As the metal ages and undergoes weathering, it doesn’t hold its original color and often becomes washed out and spotty. The best way to overcome this issue is to buy resin coated roofing coils or panels, which will age much cleaner over time.
- Denting – Since aluminum roofing is frequently a thinner, more lightweight material, it has been known to dent easier than other metals. If a structure is underneath trees or any other object with something that could fall on the roof, another type of metal material may be a better option.
- Thermal Movement – Aluminum expands and contracts roughly twice as much as a steel roof. This generally means you do not want to “double pin” the panels if they are in lengths greater than 20’. This expanding and contracting can also cause oil canning, increased noise, and more required maintenance on exposed fasteners.
Our knowledgeable and experienced metal roofing specialists are ready to answer all of your questions. Contact us today!