Architectural Record BE - Building Enclosure

Specifying Extruded Aluminum Trim for Drywall Surfaces in Multifamily Residential Projects

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Sponsored by TAMLYN
By Rebecca A. Pinkus

Performance Characteristics and Sustainability Features of Extruded Aluminum

Material performance and sustainability are two top requirements in modern architectural design. This applies to everything from design to materials, and in the case of trim, extruded aluminum is one of the top materials. Not only does aluminum have numerous sustainability features, it also has performance characteristics that make it an affordable choice for both exterior and interior projects. In this section, we will look at what extruded aluminum is and how it is produced to better understand how and why it is an excellent material for architectural purposes.

What is Extruded Aluminum Trim?

A extruded Aluminum trim illustration

Extruded aluminum is made from alumina, which undergoes smelting and alloying processes that produce solid billets of cast metal. These billets are later pressed through a die to create the desired shape of the extruded trim product.

Aluminum is the most abundant metal in the earth’s crust, although it is always found as a compound, often with bauxite ore, which contains around 30 to 60 percent aluminum oxide (known as alumina). Aluminum can be extracted from the bauxite and then smelted to form the aluminum metal that most people know. Because it is lightweight and durable, works in alloys, and is readily available through new extractions and recycled materials, aluminum is widely used in the transportation, packaging, and construction industries. It resists corrosion and is tolerant of high temperatures, making it ideal for commercial aircraft. It also is non-toxic and has low reactivity to light, water, and oxygen, which is ideal for food packaging as well as construction purposes—from windows and roofing to structural frames, gutters, and external and interior trim.

In order to get these versatile products, alumina first must undergo smelting and alloying. During this process, solid billets of cast metal are created, and these are later extruded through specialized forms in order to create the finished product. Following the extrusion process, the material is finished with anodizing or painting. The finishing process provides a range of colors, textures, and brightness to the aluminum.

Most extruded shapes used for architectural purposes are made from Type 6063–T5 aluminum. This aluminum alloy made with magnesium and silicon is commonly referred to as the “architectural alloy.” It has a very smooth surface that is well suited for anodizing applications. The T5 designation indicates that it has been artificially aged and moderately heat treated.

Characteristics of Extruded Aluminum

Image of extruded Aluminum trim in a warehouse

Type 6063–T5 aluminum is used for most extruded shapes. It is an aluminum alloy made with magnesium and silicon, and it has a very smooth surface that is excellent for anodizing. “T5” indicates that the material has been artificially aged and moderately heat-treated.

Extruded aluminum is frequently referred to as the “miracle metal” because it has such an extensive list of favorable properties. These properties make it ideal not just for transportation uses such as commercial aircraft and trucking or food packaging, but also for many different applications in the building industry. Let’s have a closer look at these characteristics that make it such a sought-after material for architectural purposes.

Physical and Health Characteristics

Aluminum’s physical properties and characteristics are at the core of its versatility. As a material, it is strong, durable, and resilient, all while being lightweight. Where some materials are damaged on impact, aluminum can spring back (or be pushed back) to its original form. And, unlike other metals, it doesn’t rust, thanks to its own naturally occurring oxide film.

Moreover, aluminum poses no health or physical hazards. It is fire resistant and noncombustible, and even at extremely high temperatures does not produce toxic fumes. According to the Occupational Safety and Health Administration (OSHA), aluminum trim products are safe enough to be classified as “articles,” which means they do not require published safety data sheets.

When used for interior architectural purposes, aluminum trim can withstand daily use and long-term wear and tear better than most other materials, and that makes it a great option for multifamily residential projects. For example, it’s tough enough to protect corners and bases, and unlike trim made from either PVC or wood, it won’t deteriorate, warp, or be prone to insect damage. Extruded aluminum trim is also lightweight and very easy to install, and those features alone can be a great time and money saver during construction.


As a green building material, aluminum has a lot going for it. Yes, it’s an abundant natural resource, but it’s also recyclable, and most aluminum is made from 75–100 percent post-industrial and post-consumer scrap. With characteristics of strength and high durability, products made from aluminum last a long time before they need to be replaced and recycled. And, as a lightweight material (at least one-third lighter than other metals), it is less expensive to transport than other metals traditionally used for architectural purposes.

All of these attributes mean that aluminum products can help earn LEED v4 certification. Specifically, they can help earn certification in these areas:

  • Energy and Atmosphere Credit: Optimize Energy
  • Materials and Resources Credit: Building Product Disclosure and Optimization – Environmental Product Declaration (EPD)
  • Indoor Environmental Quality Credit: Low-Emitting Materials

Finally, aluminum is the only material that more than pays for the cost of its own collection. As a 100-percent recyclable material, recycled aluminum saves more than 90 percent of the energy costs needed for primary production and generates only 8 percent of the emissions. Once the material is produced, it can be recycled indefinitely. As an interesting side note, approximately 75 percent of all aluminum ever produced is still used today.

Aesthetic and Design Characteristics of Aluminum

Given its physical characteristics, health and safety benefits, and overall sustainability, it’s nice to know that aluminum is aesthetically versatile in terms of the forms and shapes that can be created, as well as the finishes and polishes. Extruded aluminum can be made into highly detailed designs and unique shapes, which then can be finished in a wide variety of textures, colors, and polishes. This versatility means that designers working on interiors easily can match the finishes of doors, windows, frames, and other interior features to create a unified interior design theme.


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Originally published in Architectural Record