Painted Aluminum Panels

by Stacy Rinella | December 5, 2024 7:55 am

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More modern building designs are turning to architectural aluminum panels to make a statement with their facades. Whether the desired visuals are sharp metallics, earthy mattes, or vibrant colors, painted aluminum can provide an incredible range of finish and gloss. These aluminum cladding assemblies provide protection from the weather and are abundant, economical, and highly recyclable. Aluminum walls are a good choice for performance, sustainability, and affordability. There are many options for exterior metal wall systems, and two of the most popular are plate and composite.

 

Reviewing cost and strength

When it comes to cost, “There’s always going to be a preference for MCM over plate. The only exception to the rule is if you have a very small project that needs a custom color, then post-painted plate shines,” explains Neil Ferdowsi, vice president of Cladco Ltd., a North American panelized architectural company of fabrication, distribution, and installation. He also sees plate as an option for when the architect specifies welded corners, though the choice has become less common. “It’s a substantial price difference because the welding is very time-consuming without much functional use,” he notes.

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According to Ferdowsi, there are two additional circumstances where plate has an advantage. “With ultra-complex geometries, you can completely weld the plate and grind it smooth before painting, and of course, combustibility. Generally, outside of those areas, MCM is going to be the better option.”

Ferdowsi addresses his customers’ concerns frankly. “Some architects believe that plate is a stronger product just because it weighs more; that if it’s heavier, it’s a better product.” From his experience, MCM with an exceptional strength-to-weight ratio performs, ‘relatively the same.’ Plate is not going to outlast MCM significantly better, but it is heavier, making it more expensive to handle and fabricate.”

 

Engineering judgments

Fire protection engineers are used to evaluate wall assemblies to confirm compliance with building code requirements. They work with building owners, code officials, commercial laboratories, manufacturers, and the design team to review a near-infinite possible combination of products and construction configurations to ensure life safety.¹ They are often called in to help navigate locality-specific code concerns like those found in Ontario.

Beginning in 2025, the province of Ontario will align with the National Building Code of Canada (NBCC) on its use of MCM. “Previously, for projects more than six stories, you had to get an engineering report from a fire consultant, in a process referred to as an alternative solution,” explains Ferdowsi. “You have seen MCM projects of all sizes and heights, even in Ontario. Most consultants are very comfortable with it,” Ferdowsi says, confident in the appropriate use of MCM.

For Ferdowski’s team, there are clear advantages to MCM beyond price as well. “It’s more flexible, it’s lighter, it’s more manageable, it doesn’t have oil canning, one of the biggest factors with plate products.” However, he acquiesces that there is a segment of the market that wants a non-combustible product, regardless of code definitions and testing.

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Pre-and post-finished plate

Rick Marcovecchio, vice president at Bamco, an employee-owned architectural facade company, explains that coating a plate with the desired finish changes its price, process, and workability. When delivered as a mill-finished solid plate, as is the case with a post-finished plate, the cost of the panels drops significantly but increases the steps and timeline for a finished product.

The unfinished goods are first fabricated, then sent to painters, and returned to the fabrication shop for additional detailing before the panels can go out for installation. “I have to send it out to the painter, and I’m then obligated to their schedule. It could mean delays for our customers and our field team.” Marcovecchio also has concerns about the panel protection from the paint shop and details that the panels may need to be wrapped and re-wrapped multiple times. “One thing to know with post-painting is this is a manual process. So, you’ll get more inconsistencies compared to pre-finished plate.” To combat these quality and timeline concerns Bamco has invested in their own paint shop for projects where pre-finished plate is out of budget.

 

Comparing pre-finished plate
and composite

Reviewing the options, pre-finished plate and MCM are closer in comparison with their fabrication process. “I started my career here doing ACM, and it’s easier. It’s a process I know very well,” says Marcovecchio. Because of the density of plate, he notes that machines run at a slower speed and routing plate is a bit more difficult. Further, unless purchasing a significant volume, “pricing hasn’t been that great with pre-finished plate.”

However, Bamco is leaning into the plate space to be more competitive in the marketplace. “New York City has become the place for plate, it’s actually specified a lot more,” he explains. Updates to the NYC Buildings code state that combustible exterior wall coverings shall be limited to 12 m (40 ft) in height above grade plane, a unique modifier within the US. With much of their work coming from the five boroughs, Bamco has made considerable capital investments to improve operational efficiency to work with plate.

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Key considerations for the fabricator and the architect

“The main difference between the products I point out to fabricators is that plate panels are slower to fabricate, require more stiffening than MCM, and more equipment,” explains John Robis, principal of Exterior Technologies Group and ALPOLIC’s regional representative in Canada. He details plate fabrication may require a hydraulic shear for cutting, a press brake for bending, and a welding station to weld the corners. “All equipment requires skilled labor and takes up valuable shop real estate. Whereas MCM only requires a CNC routing table.”

Robis finds the extra labor and logistics of post-painting solid aluminum a deterrent, preferring the streamlined process of painted MCM² shipped directly to the job site following fabrication. “This not only saves time and coordination efforts but also minimizes panel damage risk due to the extra handling.”

For the design community, Robis highlights the visual considerations. In addition to being susceptible to oil canning, “Aluminum plate panels are batch painted. MCM is coil coated. You should look out for visual inconsistencies across each plate batch, which can be avoided with MCM produced from the same coil run.”

 

Combustibility

Aluminum plate is a non-combustible material. The composite core of MCM is a combustible material. That distinction is, for many, the key differentiator between the two cladding options. “It comes down to perception. I can pull out the building code and show someone both products are approved, but for some, the term combustible is a hurdle,” says Robis.

International incidents have brought a sharp focus on the use of combustible cladding. Thankfully in North America, there are safeguards within both the US and Canadian building codes that detail what materials are acceptable in different applications. Strict code compliance has ensured North America has not had to compromise on building safety.

Combustible cladding like composite with a mineral fill fire-resistant core, can be used safely in a variety of construction types. Stringent fire testing standards like those set out in the US NFPA 285 and the CAN ULC S134 use full-scale wall tests³ that ignite and measure fire spread. This is to ensure that the real-world applications of any wall assembly pass the fire standards that keep us safe.

When used correctly and in accordance with established building codes, MCM with a fire-resistant core is a safe part of the building envelope and can pass these multi-story tests designed to ensure that a fire will not spread from floor to floor. “Aluminum panels, when tested as a part of a well-engineered wall assembly, perform very well. Whether that’s plate or fire-resistant MCM, neither propagates the fire. When the heat source is removed, they both perform in a very comparable way,” explains Robis. The fire-resistant composite core has properties to absorb heat from a fire and release water to help cool the area, which enhances the fire safety and resistance of the building.

Painted aluminum panels are one of the many options for building cladding and there are benefits to each of the main product types, MCM and plate. Balancing performance and appearance is an important consideration when selecting building material, but with the right MCM, you can get the look you want that will last without compromising on either.

 

Notes:

¹ alpolic-americas.com/blog/why-mcm-preferred-in-architectural-projects/?utm_source=MetalArchitecture&utm_medium=Native&utm_id=MCM-Plate

² alpolic-americas.com/news/the-evolution-of-coil-coatings-and-paint-systems-for-metal/?utm_source=MetalArchitecture&utm_medium=Native&utm_id=MCM-Plate

³ alpolic-americas.com/blog/alpolic-announces-latest-certified-s134-fire-test/?utm_source=MetalArchitecture&utm_medium=Native&utm_id=MCM-PlateMCM-Plate&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIGCAEQRRg60gEKMTAzMzc3ajBqNKgCALACAA&sourceid=chrome&ie=UTF-8

Michael Bowie is the technical services manager in the ALPOLIC Division of Mitsubishi Chemical America. After a decade of hands-on experience with MCM’s production and quality assurance, he stands ready to answer your technical questions. Learn more about how MCM can fit into your next project by scheduling an AIA-accredited continuation education course today.

Source URL: https://www.metalarchitecture.com/articles/painted-aluminum-panels/

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