County Administration South - Exemplifying Sustainable Precast Design in Santa Ana

The final $162 million design features a six-story office building on top of two levels of underground parking, with a freestanding 7,200 sq ft conference center. The owner originally wanted the feature walls to be made of sandstone to match the courthouse; however, that wasn’t a cost-effective option, says the project’s architect, Melody Tang of LPA Design Studios. Instead, the design team elected to construct the feature walls out of colored precast concrete that was designed to exactly match the color of the sandstone while also meeting other project goals. “The ability to seamlessly blend freestanding architectural precast concrete walls around the site and ground floor with an efficient, lightweight, thin precast concrete shell was critical in achieving the overall design aesthetic,” Tang says. 

The design team reviewed many material samples with the precast concrete fabricator before finding the right match for the project. The final solution features an integral-colored precast concrete to emulate the rich red color of the historic sandstone, and thoughtful detailing of mitered corners and full returns of the panels gives the precast concrete the appearance of natural stone. “This accomplishment was made possible thanks to close collaboration between the construction manager, the precast concrete producer, and the architect,” Weekly meetings throughout the course of construction ensured that aesthetic goals were met while taking into consideration logistical challenges of casting the panels at the plant, transporting them to the site, and installing and aligning them in the field. 

To enhance the energy efficiency of the design, spray foam insulation was applied to the thin-shell precast concrete at the plant. “Attaching insulation directly to the skin of the panel minimized heat transfer between the exterior and interior of the building,” says Jeremy Hart, Director of Civic and Cultural Design for LPA Design Studios. That helped the building receive a LEED Silver rating and reduced its projected energy use from the baseline standard by 76%. “An efficient building skin was critical to the ability to achieve performance goals established by the owner and design team,” says Hart. 

The County Administration South project exemplifies how advanced precast solutions can deliver both aesthetic and functional benefits. The building’s use of integral-colored precast concrete was pivotal in achieving the desired look of historic sandstone, a cost-effective alternative to actual stone that provided both durability and long-lasting visual appeal. This choice was particularly significant given the building’s location in a bustling urban setting, where the efficiency and speed of precast installation minimized disruptions and facilitated a swift project timeline.

The collaboration between the design and construction teams, including Willis Construction, LPA Design Studios, and the construction manager, was critical to the project’s success. Regular coordination ensured that the precast panels met all aesthetic goals while accommodating the logistical challenges of casting, transporting, and installing the panels. This teamwork allowed the project to be completed five months ahead of schedule, demonstrating the value of using precast systems in complex projects.

Moreover, the innovative application of spray foam insulation at the plant level contributed significantly to the building’s energy performance. By directly attaching insulation to the precast panels, the design minimized heat transfer, which was crucial in helping the building achieve a LEED Silver rating. This efficient building skin reduced projected energy use by 76% compared to the baseline standard, highlighting how precast solutions can contribute to significant energy savings and sustainability goals in modern construction.