A battleship. That is an application that most people equate thick metal plates with. But for architects looking for creative and unique design solutions, metal plates are proving to be a robust, viable and aesthetically versatile building component when used as foundation, framing or cladding for buildings.
Sometimes thicker is better, more versatile, appealing and durable
Metal plates used as exterior cladding. Photo: Lucas Fladzinski, courtesy of William Duff Architects
METAL PLATE PLUSES
Metal plates have different aesthetic properties and characteristics than comparable materials. They are used in building applications where durability is more important than saving weight; they are corrosion and abrasion resistant.
“Solid metal plates are a beautiful and very long-lasting material, especially if they are fabricated out of weathering steel,” says Steven Ginn, founding principal of Steven Ginn Architects, Omaha, Neb. “Metal plates last longer, require generally less maintenance and are less prone to damage by inclement weather and vandals.”
At this medical examiner’s office, Corten steel plates weave the building into the landscape, provide a series of passive barriers around the building and reinforce entry points into the building. (Photo: Nathan Bortz, courtesy of LEO A DALY)
Lee Ann M. Slattery, sales support manager at ATAS International Inc., Allentown, Pa., explains, “Metal plates install quickly and easily in horizontal or vertical orientations with a dry-joint design incorporating metal splines to create the reveal appearance. They are ideal for all types of commercial, educational and health care buildings, as well as multifamily residential and mixed-use buildings. They excel at providing a smooth, flat aesthetic to a resilient building envelope. You don’t have to worry about delamination because solid metal plates don’t have plastic or foam cores. Metal plates may offer a higher level of high-quality paint finishes due to their ability to be post coated and cured in a controlled environment when custom colors are desired in small quantities.”
Because solid metal plates are durable and very good at holding a clean, consistent edge, William S. Duff Jr., founder and managing principal at William Duff Architects, San Francisco, explains one of their benefits is they can hold a very tight and continuous reveal between two metal plates. “This is helpful in composing an elevation, a component of a building or cladding. They can also be mounted or supported differently than other materials—a solid metal plate can hold a cantilever with a very thin profile. In other words, its self-supporting properties allow one to express a design differently than other materials because it can extend beyond its supporting structure further than other materials with a thinner profile.”
Metal plates benefited the National Museum of the Army, Fort Belvoir, Va. Photo courtesy of METALWËRKS
Steven Anderson, associate, senior architect/national laboratory specialist at LEO A DALY, Minneapolis, says metal plates have unique strength, geometric and durability properties that lead to unique design opportunities. “Metal plates are distinctive in the ability to create a thin planar expression without compromising strength or durability. We are able to create an organic form that will weather naturally over time and blend with the landscape. Plates have the ability to reinforce support members and also the potential to become a unique aesthetic expression while performing a structural function. Plates provide an ability to create unique geometries that are durable, thin and constructable with few materials.”
With a melting point of over 1,200 F, aluminum solid metal plates are considered a non-combustible cladding material within building codes. Because of this, they can be used adjacent to heat sources. “We’ve used them for fireplace surrounds because the same material can be used to clad the entire fireplace surface,” Duff says. “A metal plate can go right up next to a combustible edge, which allows for a cleaner, more modern look.”
Solid metal plates can be used to wrap an I-beam or a welded box section column. Duff explains, “One can attach a metal plate to either using a welded joint to get a continuous expression of the architecture, which allows the structural frame to blend seamlessly into the other components of the architecture. [Also,] they can consistently hold a flat surface over a larger surface without oil canning.”
The William M. Lowman Concert Hall in Idyllwild, Calif., is sheathed in metal plates. This skin alludes to the music within the Hall and to the landscape of folded rock and granite that makes up the surrounding mountains. Photo: Sharon Risedorph, courtesy of Sander Architects
ALUMINUM
The most common material used for metal plate is aluminum, which has a high strength-to-weight ratio. “Solid aluminum plate is available in a variety of sizes in architectural quality; complex and large shapes are highly achievable,” says Stephen Scharr, president and director of business development, Metalwërks, Kennett Square, Pa. “Solid metal plate is highly customizable. Aluminum plate is light and has excellent formability characteristics. In addition, it can be welded and polished to a furniture-like appearance for high-quality appearance. Most plate manufacturers coat the product after fabrication, which enables each component to have full coating coverage and protection. Powder coating, anodizing and PVDF wet-coating systems provide the architect with an almost endless variety of colors and textured finishes.”
Often curtainwalls, windows, louvers and doors are coordinated with the façade wall panel joint modules. “Plate panels can be easily coordinated with these openings to provide a coordinated appearance in joint rhythms,” Scharr says. “[Also,] plate panels can be formed and reinforced to be cantilevered off the building structure to create dramatic self-supporting fins and cornices. Metal plate can be easily curved. Pattern cutting and welding to a seamless appearance is a common application for dramatic designs.”
PLATE PROPERTIES, CONSIDERATIONS AND LIMITATIONS
Dan Yudchitz, associate, design director, LEO A DALY, explains that to fully optimize metal plate possibilities, discuss design ideas early with fabricators to identify construction and fabrication opportunities and limitations. Also, “It is important to understand the properties of the metal plate materials that you are designing with. This includes the relationship of geometry and methods to strength and how to connect to other materials. Also, [discuss and understand] how to make connections between plates and accommodate movement. There are situations where a series of lighter weight layers make sense, particularly in cladding applications.”
Metal plates used as exterior cladding. Photo: Lucas Fladzinski, courtesy of William Duff Architects
Ginn advises determining whether the metal plates have concealed fasteners or exposed fasteners. “Concealed fasteners are more expensive but generally look better and last longer with less maintenance. However, with concealed fasteners, when the plates must be replaced, it is more difficult and labor intensive. The other key decision is whether they are used as a permeable rainscreen or a watertight weather barrier. In my experience, rainscreen installations are more common, but special care must be taken to avoid creating inviting environments for insects.”
Duff cautions that when not treated properly, metal plates can corrode. “In high traffic and corrosive or wet environments they may not be the best choice. Another limitation is that if the material needs to be modified on a job site, it requires more labor, effort or special equipment than other materials.” Slattery notes that metal plates should not be used when the weight of the wall system is of concern.
Scharr adds that for small format plates, “When the panel modulation desired is less than 24 inches nominally then the plate investment becomes less worthwhile unless extreme impact resistance is desired. In those cases, a lighter gauge material may be a better investment.”
Overall, Whitney Sander, principal, Sander Architects, Marina del Rey, Calif., contends that when properly considered and detailed, “Metal panels can last the lifetime of a building. Their ornamental properties and the material’s acceptability for many finishes can bring true luster to many building exteriors.”
Graphics on metal plates. Photo courtesy of pod architecture + design