Tag: water-tight metal roof

Metal Panel Installation: Surface Considerations and Building Applications

Posted on by Ken Buchinger

In our last blog post, we outlined the steps to take before metal panel installation to ensure projects are built to last. In this post, we’ll take a look at the important metal panel installation considerations that should be made, particularly when working with varying surface conditions and building end-uses.

Surface Considerations:

During the installation of metal panels, it is critical that installers:

  • make sure everything is square and on a level plane (i.e., plumb and true). If it’s not, it will need to be corrected. Note: It is not recommended that the building owner do this themselves unless they are experienced and comfortable assuming the associated risks.
  • ensure the integrity of the substrate is not compromised. If installation issues or delays are caused by faulty substrate, for example, the parties responsible for the substrate would need to correct the causal issue. In retrofit projects, existing substrate issues must be addressed, but it is likely that the original builder will not be able to be sourced to correct the problem. In this case, a roofing consultant or knowledgeable substrate tradesman can help advise.
Installing Metal Panels with Different Building Applications

While installation is generally the same for most end-use applications, some equipment may vary. Depending on the other products or materials in the mix, there are certain caveats to keep in mind. For instance:

  • Over Asphalt Shingles: While installing a metal roof over an existing asphalt shingle roof is possible, it is not recommended to place metal panels directly over asphalt. In this scenario, keep in mind that:
    • It’s best to remove asphalt shingles or use a furring strip to create a buffer. (This means you can use a 1” x 4” piece of wood to provide clearance between the asphalt shingles and the metal panels.)
    • It’s not ideal to lay underlayment on top of asphalt and then install a metal roof because the shingle will curl and those imperfections will show through the metal, particularly when using lighter gauge.
  • Over Dissimilar Metals: Do not let your metal panels come into contact with dissimilar metals or allow run-off water that has been in contact with dissimilar metals to come into contact with the metal panels.
  • Over Treated Lumber: Separator material can be recommended by your installer or preferred material provider (lumber yard, home improvement store, etc.) and should be used; appropriate fasteners designed to be used to connect treated lumber with metal panels should always be used in these cases as well.
Other Metal Panel Installation Considerations:

The need for the following features and considerations can vary based on projects.

  • Vapor barriers
  • Ice and water shields
  • Regardless of all else, you’ll always want to be sure local codes/Homeowners Association (HOA) requirements are met.
Final FAQ:

How to choose a Metal Panel installer? End-users can request a list of nearby installers who may be able to help with their project from their metal building material supplier. Material manufacturers do not make these recommendations.

What if your panels are installed incorrectly? Let the installer know about any issues as soon as possible and work to get them resolved quickly. If you think the improper installation jeopardizes the product warranty, please advise the company that sold the material to you (metal panel distributor) as soon as possible. They will work with the manufacturer to resolve any warranty issues.

For more information on metal panel installation considerations or to find a metal panel distributor or installer in your area, contact your local ABC representative.

 

Galvalume® vs. Galvanized Metal Roofing

Posted on by Jessica Taylor

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.