Sir Winston Churchill got it right when he said, “We shape our buildings; thereafter they shape us.” From lofty metal-and-glass skyscrapers that house corporate America at work to the traditional brick structures that educate and mold our future leaders, the most visible element of our industry’s presence is clearly building façades and exteriors.
Curtainwall
Although curtainwall is a term that was once used to describe the set of walls that surround and protect the interior (bailey) of a medieval castle, both the technology and term have evolved to take a prominent place in modern architecture. Unlike medieval castle walls, modern curtainwalls are not structural; they are an attachment. The curtainwall framing, usually aluminum, is “hung” on the building structure by bolting or welding, and the glass, stone, aluminum, etc. in both vision and spandrel areas is installed in the framing.
Over the past 30 years, the industry has experienced a near-revolution in the availability, versatility, and cost of architectural stone through thinner dimensional - “thin-set” - stone, and anchoring and attachment systems have added to stone’s growing popularity. Latest developments of curtainwall technology include “unitizing” or “unit system” construction, which entails factory pre-fabrication of panels and, in some cases, factory glazing. These completed units are hung on the building structure to form the enclosure. Of particular note now - and into the future - are the technologies being applied to these systems to take curtainwalls to a new level of performance and opportunity, particularly the integration of photovoltaic cells to produce electrical energy by capturing sunlight.
Brick Masonry
The use of brick as a building material dates back centuries. In fact, its enduring qualities and limitless appearance adorn the walls of many traditional structures. While brick and structural clay tile are both visually appealing and durable, they are also well-suited for many structural applications. This is primarily due to their variety of sizes (which influence the scale and appearance of a building) and very high compressive strength. The material properties of brick and structural clay tile, which have the most significant effect upon structural performance of the masonry, are compressive strength and those properties affecting bond between the unit and mortar, such as rate of water absorption and surface texture.
Sustainability initiatives and a return to traditional elements have influenced brick’s resurgence as a building material. Today, brick manufacturers offer a wide variety of colors - from reds and burgundies to whites and buffs. Textures, which interact with light and create differing and interesting shadows, range from smooth, wirecut (velour), and stipled to bumbled, brushed, and more. Since brick can be molded and formed into any shape, unique design features are easily achieved.
Exterior Insulation and Finish Systems
Exterior Insulation and Finish Systems (EIFS) are multi-layered exterior wall systems that provide superior energy efficiency and offer great design flexibility. Developed in Europe in the 1950s, EIFS were introduced in the United States almost 30 years ago. EIFS typically consist of the following components: insulation board, made of polystyrene or polyisocyanurate foam, which is secured to the exterior wall surface with a specially formulated adhesive and/or mechanical attachment; a durable, water-resistant base coat, which is applied on top of the insulation and reinforced with fiber glass mesh for added strength; and an attractive and durable finish coat - typically using acrylic co-polymer technology - which is both colorfast and crack-resistant.
As with all claddings, EIFS must be correctly installed and properly detailed if they are to perform properly. Otherwise, moisture can get behind the systems and cause damage, just as it can with wood siding, brick, or any other exterior. Key to this is verification from the manufacturer that the project plans and specs contain sufficient information and details (regarding windows, doors, flashing, sealants, etc.) to provide a weathertight building envelope, as well as examination of the substrate for proper tolerances, cleanliness, etc. Today, most EIFS are specially formulated with a 100-percent acrylic binder, which gives EIFS superior resistance to fading, chalking, and yellowing. As a result, the systems tend to maintain their original appearance over time - offering both initial and life-cycle costs that will appeal to any owner.
Sources include The Brick Industry Association (www.bia.org), Reston, VA, and the EIFS Industry Members Association (EIMA) (www.eima.com), Morrow, GA.
