Robert G. Little, Jr., AIA
Senior Design Principal
The combination of exterior building envelope and MEP systems can represent 60% – 80% of the capital expense for new building construction. These systems are uniquely related.
Currently, energy code requirements dictate design parameters that require the building mechanical systems meet a minimum energy performance thresholds. Every couple of years the thresholds of acceptability moves higher as new code guidelines drive greater sustainability and costs associated with the building engineering systems continues to prove challenging. The building exterior envelope, therefore, is a contributor of that equation and provided opportunity for cost efficiency, aesthetics, and energy performance.
As we further examine the relationship of aesthetics, capital, and revenue models for a developer-driven asset, for example, solutions for an exterior envelope can provide a great opportunity to dramatically enhance the successful outcome of an initiative. If we use the developer model as a case study, the cost of capital deployed for the exterior envelope and MEP systems represent a significant portion of the construction cost as we discussed. Therefore, when these elements are properly managed, the returns resulting from the asset are enhanced as the first cost of capital inform lease rates or margins in a transaction. In that environment, we, as architects, look to uniquely balance the first cost of capital with aesthetics, market conditions, and construction to help to enhance our client’s proformas.
Based on this context, architectural precast concrete wall panels offer an excellent choice towards a cost-effective façade. Good economic value can be realized if the panel design is replicated numerous times, and if the building is large enough to justify precast as the project site logistics make possible a quick timeline for construction.
As an architect learning my trade in an era of precast-panel overuse, it was easy to overlook the opportunities afforded by this material. There was a time when many architects, including myself, thought very little of precast panel facades. Over time, my design sensibilities have matured to appreciate the plasticity of architectural precast. I have learned that it can be a truly wonderful material if used appropriately and creatively. I like to tell younger architects on our teams, “It’s not your father’s precast.”
The material offers advantages of scale and pattern. A building’s character morphs as the sun passes overhead, creating opportunity for changing shadow-play from dawn to dusk. Designing shallow reliefs into precast panels builds interest, beauty and movement into these seemingly static, monumental forms.
Three recent projects completed by L2P highlight the use of architectural precast concrete panels. The first is an office building in Chadds Ford, PA, where the use of relief shadowing provides visual interest on an otherwise modest three-story, 75,000 SF building and gives an apparent lightness to the façade. Here, the horizontal panels feature a seemingly-random pattern with a 1” projecting horizontal warp. This gentle relief creates subtle to dramatic shadowing depending on the time of day. Many are surprised to learn the apparent softness of this façade is achieved using concrete.
At a much larger scale, the new laboratory facility in New Castle, DE, sprawls with 350,000 SF over two floors. The economics of the project dictated the use of a multistory vertical pre-cast panel design with cast-in window openings. The team designed 7½” thick panels with a series of varying-width folding vertical bands creating a total off-set relief of 1½”. The shadows created by this vertical banding distort the sheer length of these nearly-400’ facades down to a more pedestrian scale. The gesture creates an affordable, simple, and attractive solution for this developer-driven science and technology project.
Our final focus is on a new facility designed for a medical device manufacturer in Reading, PA. A very limited core and shell budget had led the development team to discard all but the simplest of designs for this tenant. Partnership with L2P architects offered a fresh approach to the single-story building. Here, graceful 32’ high, 8” thick vertical precast panels with cast indentations up to 2” deep created variation in the sharpness of the structure and changed its appearance throughout the day. The pattern was created using a combination of ½ round vertical flutes and rectangular shapes in the form work and gave remarkable character to this modest investment.
Pride in the integrity of simple materials led these project design teams to employ precast concrete panels honestly, without attempt to simulate other materials, such as stone, with reveals or cast texturing. Precast concrete is a malleable material, easily repeatable and possessing its own character. The plasticity of concrete and the cost effectiveness of this common material has endless inherent design potential that makes it a good choice for many project types.