Aluminum, which is often referred to as a "miracle metal," is the second most widely used metal in building after steel. First, used as decorative detailing and then in roofing, flashing and wall panels, it is now considered as a construction material that is energy-efficient and sustainable. In the United States, aluminum-intensive Leadership in Energy and Environmental Design-certified (LEED) buildings have won awards for sustainability, thereby making aluminum the building material of choice. Used in residential and commercial construction often as external cladding and building facades, aluminum composite panels (ACP), a flat panel made of two thin aluminum sheets bonded to a non-aluminum core, combines aesthetics, durability and affordability while providing environmental benefits.
Aluminum is available in a variety of lengths and widths and can be easily formed into various shapes as it can be bent, curved and joined together in many different configurations. Some manufacturers produce ACP that snap together and can be installed on wood frame, concrete, or steel studded buildings. The use of aluminum in building projects helps qualify for green building status under LEED standards because it is easily recycled. It loses none of its properties during the recycling process, which reduces the use of energy by over 90 percent versus the higher energy-intensive process required to produce new aluminum from raw materials.
Aluminum composite panels, though as strong as steel, are lightweight, thereby saving costs by reducing structural steel support requirements. Not only can structures made with aluminum weigh up to 65 percent less than steel, but aluminum is durable, resistant to corrosion, and requires minimal maintenance. It is not required that ACP be painted, but they can be finished in virtually any color and remain consistent from one panel to the next. They can also be etched with designs and made in patterns that resemble other materials, such as wood or marble. Aluminum panels are cost effective in that they can typically be installed faster than alternative exteriors such as granite or brick. Maintenance costs are reduced because panels eliminate the concerns over mold and mildew and retain their luster for years. Energy costs are also reduced as ACPs help provide insulation.
One of the disadvantages of using aluminum composite panels is that noise is sometimes caused by rain falling on aluminum. Aluminum panels of an inferior quality and that have not been reinforced in the manufacturing process to make them more susceptible to damage can easily be dented, especially when forcefully struck by heavy rain. Likewise, aluminum panels may become scratched, and pre-colored aluminum panels may fade or turn chalky when exposed to the elements after only a few years.
Although aluminum panels are a great barrier to air and water, waterproofing is necessary or moisture will enter the seams around or above the panels. Furthermore, aluminum panels reduce construction time and labor costs as they can be installed all year long, including periods of unpleasant weather. However, they are more expensive compared to traditional materials.