The facade of a building plays a key role in the overall design perception of a building as well as its ability to perform favorably. As the visible public “face” of a building, it provides a means for design expression that can range from traditional to innovative, planar or three dimensional, static or dynamic, colorful or not. Architectural critics in multiple media platforms expound on the relative merits and deficiencies of particular building facade designs while the general public reacts with vernacular zeal for what it likes or doesn’t like. From a performance standpoint, facades often provide the largest surface area of the building enclosure, thus having a very direct impact on the long-term durability and energy performance of the building. Of course, the particulars of the facade need to be based on the local conditions to respond not only to design preferences but to performance issues as well. The Architecture 2030 organization defines this point by saying, “A climate-based building facade is a filter between exterior and interior that creates comfortable internal living conditions.”¹ As such, a facade design determines what filters in (e.g., sunlight, fresh air, etc.) and what is filtered out (e.g., excess heat, noise, etc.) all in the context of good design principles.

Photo courtesy of Construction Specialties

Building facades are key elements in both the design and performance of a building with many choices available in products, materials, systems, and solutions.

In the quest for a high-performing, well-designed building facade, architects need to rely on their understanding of the plethora of available materials, products, systems, and solutions on the market. In this course, we will look at some of those commonly available choices with an eye toward achieving innovation and high performance in building designs.

Integrating Structure and Facade

In a three-dimensional building exterior, sometimes it is the design intention to connect the inside with the outside, blur the visual sense of the enclosure, and provide daylight and views while still providing shade. By expanding the definition of a facade to encompass the entire outward expression of a building, its exterior form, its extended parts, and overhangs, the aesthetic and architectural value can be enhanced. Interconnected three-dimensional exteriors can provide opportunities for light sources to play with interior spaces, create an artistic continuation of themes from the outside to the inside, and generate overall impressions that delight the users and visitors to a building. Achieving these design results does not need to be elaborate or complicated. In fact, some of the best solutions often rely on simple, elegant design approaches and common building materials. One example that we will explore here is the use of structural steel decking systems to create innovative and high-performing facades.

Horizontal Projections

Steel decking has been used successfully to extend out horizontally past the exterior wall system to create an overhang or other design feature. A range of steel decking systems are available to address both structural and aesthetic objectives. Among these are deep ribbed or “dovetail” shaped steel deck profiles that offer enhanced structural strength plus an attractive pattern on the underside of the deck. When left exposed, this deck becomes integral to the overall aesthetic, whether serving as uniquely designed roof extensions or as integrated screens and canopies. They can also provide acoustical control when used for ceiling applications. Further, they can be longer in their span than standard steel deck, up to 35 feet in many cases. For simplified construction, lighting, electrical, plumbing, and fire suppression can all be readily integrated in the system. Of course, proper detailing is needed to assure thermal bridging is avoided, but that can be very straightforward to achieve.

Cladding

In addition to horizontal uses, vertical, angled, curved, or sloped steel facades can be created using steel roof deck profiles as a cladding material. One of the ways to do this is by using structural steel decking (i.e., found in specification Division 5) for facade cladding in lieu of the typically more expensive architectural metals (i.e., found in specification Division 7). The attachment and field installation processes are well known and can produce a consistent, controlled performance related to loading conditions. Further, the appearance can hold up well over time. It should not be a surprise, then, to realize that this steel decking is being used not only for the underside of horizontal canopies on building exteriors but also for vertical facades.

Such structural steel decking is engineered for strength and durability and comes in a variety of profile shapes and depths with a range of visual effects. These include dramatic deep flutes, ribbed patterns, a lineal plank appearance, or a clean, smooth look. When used as cladding, steel decking can uniquely address the facade objectives of function, form, and cost control. This comes about because these systems contribute both structurally as well as aesthetically to the building. They serve to transfer loads and forces into the main building structure to maintain the integrity of the building while helping to weatherproof the exterior—and they can provide the finished cladding surface all in one product.

Standard profile deck along with long-span deck can be readily installed vertically, minimizing joint lines and creating an attractive exterior cladding. The engineered corrugations in the decking can be sized to hold up against wind, weather, and usage as appropriate to the project location, making it suitable for a permanent or sacrificial skin or a rainscreen on a facade. It can also serve as a sun screen or solar shading device where appropriate.