Need to Know

• Powder coatings currently represent an estimated 25% of the U.S. architectural aluminum market despite their long-standing dominance in Western Europe.
• Architectural powder coatings are used on aluminum extrusions for windows, doors, storefront systems, curtain walls and other exterior building components.
• These coatings can meet stringent AAMA performance requirements without solvents while providing textures, wrinkles, wood-grain effects and other decorative finishes.
• U.S. adoption remains constrained by applied cost, higher film-build requirements, aesthetic limitations and well-established liquid-coating infrastructure.

Coatings for Architectural Aluminum

In the powder coatings space, the term “architectural coatings” generally refers to coatings applied to aluminum extrusions used in commercial and high-end residential building applications. These extrusions often serve as the structural component of a variety of architectural products, including doors and windows, store front systems, curtain walls, and other exterior building components. Since these products are often installed on the façade of a building, they play a significant role in its overall appearance while being exposed to years of sunlight, moisture, temperature fluctuations, and other harsh environmental conditions. As a result, both the aesthetics and long-term durability of the coating are critical.

Two general types of coating systems are used on architectural aluminum: a solvent-based primer/topcoat system or a powder coating that is applied direct-to-metal. The binder chemistry of the topcoat in either system is selected based on the level of exterior durability that is required for the specific application. These applications are highly specified, with coating performance governed by standards established by the Fenestration & Glazing Industry Alliance through the AAMA specifications. These standards define the performance requirements for properties such as exterior durability, corrosion resistance, impact resistance, and chemical resistance, with the highest performance specifications intended for the most demanding architectural environments.

Advantages of Powder Coatings in Architectural Applications

The main driver for the continued growth of powder coatings in architectural coatings is their favorable environmental profile. More specifically, powder coatings can be formulated to meet even the most stringent AAMA performance specifications without the use of solvents, while the majority of liquid coatings used in these applications remain solvent based. This provides powder coatings with a significant advantage, as many architects, building owners, and related governing bodies prioritize the use of more sustainable building materials and other technologies for green building initiatives.

However, sustainability is not the only factor driving adoption. Architects and designers also turn to powder coatings when seeking certain distinctive aesthetic effects. Powder coatings can provide a wide variety of appearances, including wrinkles, textures, and other effects that can be difficult to achieve with liquid coatings. Technologies such as sublimation expand on these capabilities, offering the ability for the finish to mimic the appearance of natural materials, such as wood grain or stone.

Remaining Challenges

Despite these advantages, liquid coatings remain the dominant technology for architectural applications in the U.S., with certain aesthetic limitations of powder coatings being one of the primary factors. Historically, these limitations have included surface smoothness, breadth of color palette, and the appearance and consistency of metallic finishes. Although advancements have been made in each of these areas, liquid coatings still maintain an edge and continued technology development is necessary to level the playing field with liquid coatings.

Applied cost also remains a challenge for powder coatings. While powder coatings can provide the required protection with a single direct-to-metal coating, liquid primer/topcoat systems are more cost effective on an as-applied basis. This is largely due to the higher total film build required for powder coatings, which typically exceeds the combined dry film build of the two liquid coating layers.

Powder coating manufacturers and applicators continue to address this cost disparity through the development of powder coatings that require lower film build. While significant progress has been made, a cost gap still exists in many applications.

Untapped Opportunities

The relatively low penetration of powder coatings in the U.S. should not necessarily be viewed as a technological limitation, but rather as an indication of the opportunity that remains. The widespread use of powder coatings on architectural aluminum in Western Europe and other regions demonstrates that the technology is capable of meeting the demanding performance requirements of this market. In the U.S., however, a well-established liquid coating infrastructure, familiarity among architects and specifiers, and the cost and aesthetic considerations discussed here have contributed to a slower transition.

As sustainability becomes increasingly important throughout the building and construction industry, the environmental advantages of powder coatings should continue to support greater adoption. At the same time, continued improvements in aesthetics and applied cost are gradually reducing the areas where liquid coatings maintain an advantage. Given the size of the U.S. architectural market and the relatively low current penetration of powder coatings, even incremental share gains could represent a significant growth opportunity for the powder coating industry.

For more information, contact the author at ecasebolt@chemquest.com or visit https://chemquest.com.

Explore more expert analysis of formulation, performance and application trends in PCI’s Powder Coating Perspectives column.