Deep in the foothills of the Rocky Mountains sits the gleaming new Temple of the Church of Latter-day Saints. The structure has become a landmark for Fort Collins, Colo., and a testament to the incredible detail that can be achieved in a precast concrete design. The temple features a steel-braced frame clad in a precast concrete envelope featuring almost 1000 architectural precast concrete panels. Its warm white color, marble aggregates, and handmade finish give it the look and feel of natural stone in a durable cost-effective package.
“The owner wanted an exterior material that could achieve the intricate detailing desired and still maintain the longevity and durability for a 50-plus year building,” explains Ethan F. Bedingfield, AIA, associate at Architectural Nexus, the architect for the project. “The design required a monolithic-looking material that could be carved away at openings. Precast concrete helped us to achieve all of these things in an economical way relative to carved stone.”
More than 34,000 ft2 of precast concrete elements of complex geometries and finishes were manufactured by Pretecsa, the precaster for the project in Mexico, then transported by road 1770 miles to Fort Collins and installed over the course of 10 months. “The main challenge was to coordinate engineering, manufacturing, and installation between all participants from 1800 miles away,” says Alex Fastag, CEO of Pretecsa.
A tight schedule and weather limitations required quick installation, which the designers achieved by creating massive precast panels that covered up to 250 ft2 each. The large dimension of the panels combined with the high complexity and precise detailing was a challenge, Fastag says. “The monumental dimensions provide a scale where fine details could be easily lost, but the demanding client required the precision expected from a precast panel.”
To accommodate the massive design, forming of each mold required joining several smaller pieces created with different materials. Plaster models of small sectioned parts were designed and subsequently articulated into molds to have larger and more complex pieces requiring a dedicated crew of cutting and profiling each section using different hand tools. A flexible three-dimensional molding system, specially created for this project, was used to achieve the rounded plaster forms. Combined molds of latex, wood, concrete, glass-fiber-reinforced concrete (GFRC), polyurethane, and polystyrene were obtained to accommodate the required finishes of each panel. Extensible molds of adjustable proportions and dimensions were manually articulated to create unique pieces with different surfaces reducing the number of casting beds needed, while straight, curved, concave, and convex molds were produced to form highly complex parts. The result was large monolithic detailed panels with fewer joints giving the project the monumentality required without losing the fine and complex architectural details conceptualized by the design firm, Fastag says.
The precast concrete design enabled the architect to achieve the intricate shape and formed details needed to generate the appearance of a carved material. “The monolithic, carved nature of the columns, pilasters, and details give the building the visual weight that it needs,” Bedingfield adds. “The precast was able to achieve the fine detailing of leaves and patterns desired.”