The introduction of new technologies and products has helped fuel the rapid growth of tilt-up over the past decade. Combined with creativity on the part of the designer, tilt-up is dispelling the perception that it is only for big-box construction.
One trend being explored involves using the unique nature of tilt-up construction to create interesting panel forms. Because concrete is a fluid material, it can easily be cast into any shape that can be formed.
Large diameter curved building walls can be constructed of flat panels arrayed along a large radius or by using several radius panels. Panel curves can be either concave or convex. Panels with curved edges or small radius panels provide softer, rounded corners for traditional rectangular buildings.
Another way to incorporate unique forms into a traditional rectangular structure is through the use of interlocking panels. These panels are cast in a variety of shapes, often using different finishes or textures to give them interest, then fitted together like puzzle pieces. This is easily accomplished since the entire elevation typically is cast as a single, divided unit on the floor.
Another way to add interest is with the use of openings. Windows and doors are the most obvious panel openings, but purely aesthetic openings, referred to as “voids,” also can bring plenty of drama to otherwise plain panels. Since the shape is cast horizontal on the casting surface, virtually any shape is simple to construct.
Imparting architectural interest isn't limited to the casting process. The way the panels are placed together can go a long way in creating an eye-catching structure. Shadow panels, overlapping panels, and free-standing panels that extend beyond the four walls of the structure are an easy way to make a statement. Shadow panels (placing one panel several feet in front of another) can give the building a dynamic effect as the sun moves throughout the day.
Another broad trend defining architectural tilt-up today is the desire to replicate traditional building materials such as brick and stone.
Although the real materials can be costly and time consuming to install, their tilt-up counterparts are fairly easy and inexpensive to incorporate. A variety of finishing techniques can impart these classic looks on a building's surface.
Reveals—narrow, decorative indentations (usually ¾-inch deep) in the face of the panel—are formed by applying strips to the slab (casting surface) before placement of the concrete. Something as small as a change in reveal depth can alter dramatically the look of the structure. The reveal forming strips have sloping sides for easy removal.
Formliners are another easy way to bring interesting detail to an otherwise plain panel. These liners are available in a variety of textures that replicate several different materials, including wood, corrugated steel, and bush-hammered concrete. Even customized images such as logos can be fabricated from foam and placed in forming beds. Vacuum-formed plastic one-time-use liners make texture an affordable option.
Although details cast into panels may work in some situations, others may warrant applied ornamentation—decorative elements added to panels once they have been formed. One of the most popular forms of applied ornamentation is exterior insulated finishing systems (EIFS).
Another way to achieve a classic, traditional style is by using cast-in elements. These elements typically are materials, such as thin brick, stone, or tile, which are cast into the face of the concrete panel.
Cast-in elements can provide the most realistic option for creating a traditional finish, however, a more popular economical approach is to apply or modify the face of the concrete once it has set. These methods include exposed aggregate, polymer-modified cement, coatings, paint, and stamped or rolled finishes.
Many of the above structures and finishes will be featured at the 2008 Tilt-Up Convention this fall in Phoenix. Visit the TCA Web site www.tilt-up.org for more information about tilt-up, finishes, or the convention.
— Ed Sauter is the executive director of the Tilt-Up Concrete Association (TCA). He can be reached at 319-895-6911 or firstname.lastname@example.org.