Galvalume® vs. Galvanized Metal Roofing

Galvalume® vs. Galvanized Metal Roofing

Selecting metal panels made from high-quality materials is essential to the longevity and success of your customer’s metal roofing system—from the steel sheets to the fasteners. Although the quality of the paint system applied to metal roofing panels provides an essential level of protection (as discussed in our recent ‘Decoding Your Warranty’ blog series), not to be overlooked is the coating used on metal roofing panels. Two coatings are commonly used on steel sheeting in the metal panel industry today: Galvalume® and Galvanized. Both products are manufactured to adhere to carbon sheeting and provide a barrier that resists corrosion. Additionally, they enhance long-term water-tightness and durability, ensuring resilience through damaging weather conditions. But what exactly are the differences between Galvalume® and Galvanized?

What is Galvalume® metal?

Introduced into the construction marketplace by Bethlehem Steel in 1972 and now widely available around the world, Galvalume® is carbon steel sheeting coated with aluminum-zinc alloy by a continuous hot-dip process. Composed of 55 percent aluminum and approximately 45 percent zinc, this coating combines the best properties of both metals. It has the corrosion resistance, high temperature oxidation resistance and heat reflectivity typical of aluminum coatings, with the formability and galvanic protection of cut edges characteristic of zinc coatings. This combination makes it ideal for most types of roofing and siding. In addition, the coating also contains a small but significant amount of silicon in the alloy—not to enhance the corrosion performance, but to ensure optimal coating adhesion to the steel substrate when roll-formed, drawn or bent during fabrication.

 What is Galvanized metal?

Galvanized Sheet is carbon steel sheet coated with zinc on two sides by a continuous hot-dip process. This method tightly adheres the coating to the steel with an iron-zinc alloy bonding layer formed by a diffusion process while the heated steel strip is in contact with the molten zinc.

What is the difference between Galvalume® & Galvanized roofing?

While both products were developed to essentially sacrifice themselves to protect the steel sheeting they coat, the above exposure comparison shows that Galvalume® performs (up to nine times) better in fighting corrosion as compared to Galvanized coating. While Galvalume® can initially show signs of corrosion faster than Galvanized, it has a sacrificial property that will prevent the corrosion from growing whereas once corrosion has started on a Galvanized panel, it can continue to corrode until panel integrity is lost. According to a study released by the Metal Construction and Zinc Aluminum Coaters associations, the longevity of a low-slope unpainted Galvalume® standing-seam roof is 60 years  (See the full report.)  Additionally, primer and paint adhere better to Galvalume®-coated panels and they carry a 20-year limited warranty while galvanized panels do not, making them a smarter long-term investment for your customers’ homes, agricultural buildings or commercial properties.

Important Facts About Galvalume®

  • Galvalume® should not come in direct contact with: standing water, dissimilar metals (copper, lead, iron), harsh chemicals, graphite pencil, masonry products or treated lumber.
  • Proper roof inspections and maintenance is still required, as with any other roof system.

Its versatility, ease of use, aesthetic appeal and long-term, service life-extending performance makes Galvalume-coated steel roof panels the most economical and sustainable coating option for your customers’ new and retrofit applications. To learn more about Galvalume®, please visit  http://www.galvalume.com/. To view ABC’s Galvalume® Plus products, which are easy to form and install safely due to the thin, clear acrylic coating that allows them to be roll-formed dry without vanishing oil, please see our color resources and Galvalume® warranty information.

Spotlight on Underlayment: Synthetic vs Felt

What’s under your customer’s metal roof matters.

Roof underlayment is the first layer of material laid prior to the metal roofing panels. It separates the roof covering from the roof deck, thus protecting it from detrimental resins, unevenness and—in re-roofing applications—fasteners and other old building materials. This water-shedding layer also provides secondary protection from weather, shields the roof deck during construction and is often required for warranty adherence and for roofs that must meet Underwriter’s Laboratory (UL) fire ratings. Outside of its traditional use, synthetic underlayment can also offer a myriad of benefits for your customers.

Synthetic vs Felt

Felt underlayment, also known as “felt paper” has been the traditional underlayment of choice for decades. It was used to prevent damage to the roof covering caused by sap leakage from wooden building materials, however—as even most wood structures are now constructed using plywood or other, non-wood materials—this is no longer an issue. Felt underlayment is saturated with asphalt composed of volatile compounds that dissipate over time. This makes it more fragile and likely to absorb moisture, which further weakens the roof. This deterioration is accelerated when asphalt is exposed to UV rays, heat, poor ventilation and less energy-efficient roof coverings. Additionally, the crude oil refining techniques that previously resulted in the creation of asphalt as a byproduct, now extract the maximum amount of product from the crude resource. As a result of this advancement in the refining process, only a powder-like residue that is not conducive to the development of asphalt is generated. Consequently, more customers are turning to a synthetic alternative for a longer-lasting, economically-efficient solution.

Compared to traditional organic felt, synthetic underlayment is significantly more lightweight, permitting many more squares per roll, which makes it an economical solution for your customers. While non-woven materials are generally moisture permeable, woven scrim synthetic roof underlayment greatly enhances tear resistance and ease of installation. While it can be designed to be moisture-permeable, synthetic underlayment is typically manufactured as a barrier that doesn’t absorb moisture, making it resistant to fungal growth and wrinkling.

Underlayment Requirements and Resources

Although synthetic underlayment may be the superior choice for your customers, it is imperative that its use does not violate building code requirements or manufacturer’s warranties for the intended roof covering and that it is installed according to the manufacturer’s provided instructions.

The International Code Council (ICC) has developed a single set of comprehensive and coordinated national model codes and standards used in the design, build and compliance processes to ensure the safe, sustainable and affordable construction of structures. The ICC’s set of International Codes (I-Codes) are available for purchase, and include, among others:
·         International Building Code (IBC)

  • International Energy Conservation Code (IECC)
  • International Fire Code (IFC)
  • International Green Construction Code (IgCC)
  • International Residential Code (IRC)

Of particular importance to the roofing industry are the IRC and IBC I-Codes. These codes include specific underlayment requirements and installation/ attachment directions for simple enforcement by inspectors. Provided in Chapter 9 of the 2015 IRC and Chapter 15 of the IBC, they cover material types, application and attachment requirements, including specific information for metal panels with denotations for variances specific to high-wind areas.

Because of the wide variety of underlayment and metal panel styles, the IRC and IBC require installation according to manufacturer’s instructions. In the absence of manufacturers’ instructions and/ or when using alternative materials, the specific requirements outlined in the IRC and IBC I-Codes should be used where applicable. Remember, a metal roof is designed to have a long service life, and the underlayment’s service life should at least match that of the metal roof. Don’t allow your customers to be shortsighted when designing for longevity by using an underlayment not guaranteed to last for the duration of their roof.


ABC Underlayment

Advantages of Underlayment

Woven, coated polypropylene synthetic underlayment fabric is not only designed to protect against weather damage, but also provides greater strength, a longer UV exposure window and more secure surface for installation safety. Some underlayment options are 100 percent recyclable and up to 25 degrees cooler than asphalt felt, which can result in decreasing energy costs for your customers. At one-fourth the weight of traditional felt, but up to 20 times stronger, it ensures longevity that can’t be matched using traditional felt, particularly in areas that experience extreme heat and weather events. To prevent downhill slide during installation, underlayment is manufactured with anti-skid coating on both sides, ensuring a more sure-footed feel is achieved once attached. In addition, underlayment is certified to withstand up to six months of exposure to the sun and other weather elements before the final roofing material must be laid.

Learn More

For more information on ABC’s metal roof and wall products and for more tips on underlayment, please contact your local ABC sales representative.

 

 

Decoding Your Warranty: Paint Fade Protection

Will a Metal Roof Lose its Color?

Paint fading is one of the biggest concerns voiced by metal roofing customers. Over time, all paint systems will fade so it’s important for your customers to understand how warranties can protect their investment. Buying a red roof that prematurely fades to pink is unfortunate enough, but this is made even worse by a warranty that doesn’t adequately protect their purchase.

 

ABC WARRANTY INFORMATION: PAINT FADING
ABC WARRANTY INFORMATION: PAINT FADING

 

Why does paint fading matter?

The paint on your customer’s metal roof or wall isn’t just for decoration. In addition to providing color, the paint finish also protects the panels from corrosion, temperature, moisture and other detrimental environmental elements. Fading is the most common source of color change over time and happens when environmental elements deteriorate the paint’s pigment (granular particles that give the paint its color). This deterioration also reduces the paint’s effectiveness in protecting metal panels.

Paint fading is measured by the American Society of Testing Materials’ (ASTM’s) Hunter unit (∆E) standard, which compares the faded color to the original. In accordance with ASTM Standard D2244, one Hunter Unit is equal to the smallest amount of change visible to the naked eye.

 

What do you need to look for in your warranty?

Selecting a product with a 40-year warranty is a great start, but not all panels, paint systems and warranties are created equal. Your customers should make sure that the manufacturer provides a warranty which clearly defines the number of Hunter units the paint system is allowed to change for both vertical (wall) and horizontal (roof) applications. This is critical when comparing one painted metal roof or wall against another. The lower the number of Hunter Units expressed in the warranty, the better the paint system will resist fading.

ABC’s Premium paint system warranty guarantees paint will not fade in excess of five units in vertical applications and seven units for non-vertical applications over the course of 30 years, with the exception of Radiant Red. ABC’s fading specification on all colors available in our Select40 paint system guarantees protection for the same degree of fade as guaranteed in the Premium system, but for 25 years. Check out ABC’s color resources and warranty information to learn more!

 

What’s next?

Understanding the film integrity and fading for metal panels is very important, but it doesn’t end there. In the final installment of our “Decoding Your Warranty” blog, we will uncover a third consideration that can help you and your customers understand metal roofing and siding warranties: chalking.

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What your customers need to know when considering a metal roof for their home

metal roofing for homes & houses

Your customers have a wide variety of options when choosing roofing materials for their home. One of those options is metal. When considering whether to use metal roof panels, there are a variety of factors any homeowner should consider.

Is Metal Roofing Right for Residential Use?

When considering metal roofing for residential applications, here are common questions your customers may have:

Will a metal roof match the style of their home?

With a wide variety of styles, profiles and colors, metal roofs compliment any residential design. Manufactured and produced to provide a higher quality option, metal roofs give your customers the beautiful appeal they want and the durability they need.

What is the life span of a metal roof?

According to a recent study by the Metal Construction Association (MCA), metal roofs are projected to last longer than the buildings they cover, up to 60 years or more. For customers considering a metal roof for their home, it’s a decision they’ll only need to make once.

How will metal roofing stand up to extreme weather?

Metal roofs are recognized for their durability and resistance to inclement weather with intense testing for high winds that can withstand gusts up to 140 miles per hour. (This is dependent upon the metal roofing profile selected. Your customers should contact the metal roofing manufacturer to assure they have the correct roof panel for their weatherability needs.) In addition to standing up to wind, metal roofs are known for withstanding decades of harsh weather like heavy snow, hailstorms and even fires. For homeowners who see a lot of heavy snowfall, metal roofs are an ideal option as they are able to shed snow fast and eliminate ice damming.

What are the environmental benefits of a metal roof?

Since up to 28 percent of the panel is recycled material, choosing a metal roof is beneficial for the environment. Metal roof are also nearly 100 percent recyclable. Additionally, they are energy efficient, absorbing up to 34 percent less heat than asphalt shingles. This keeps your customer’s home cool in the summer and warm in the winter—reducing their energy costs.

What does a metal roof cost in comparison to traditional roofing?

As a premium home product, your customers can expect their new metal roof to cost roughly twice as much as a traditional roof. However, there are many benefits that make this a cost-efficient solution for you customers including lower energy costs, moderate maintenance and increased resale value of your customer’s home. With metal roofing, your customers can be assured that they are investing in a long-term solution that more than makes up for the initial cost savings associated with traditional roofing materials. Read our blog post on metal roofing and shingles to learn more about pricing and benefits.

For more information about residential roof panels, contact your local ABC sales representative today.