Using precast panels helped a design-build team achieve a uniquely patterned facade that was quick and easy to install.
By Shari Held
The newest addition to Washington State University’s (WSU) research and education complex is the striking, 82,400-square-foot, four-story Plant Sciences building. Its facade features an intricate three-dimensional, undulating design created with embedded thin-brick precast concrete.
The massive, two-story glass and metal cantilevered entry for the L-shaped building provides shelter and a welcoming openness to the facade. On a campus where brick facades predominate, this building, which was two years in the making, stands out.
Early collaboration and input from all team members were the keys to success for this design-build project.
“The design-build process allows you to explore all kinds of ideas about product materials, architectural expression and budget and installation efficiencies,” said Eric Marsh, project executive of Skanska USA Building, the project’s design-builder. “I’m not sure we could have achieved some of the elements on this building without it.”
Achieving new heights with precast
The Plant Sciences building needed to blend in with the existing campus buildings, which are predominantly red brick, but WSU in Pullman, Wash., was amenable to exploring innovative construction methods and materials.
Both traditional brick and precast panels were considered. Precast won out for several reasons.
Seattle-based LMN Architects recently completed a Hyatt Regency hotel clad in insulated precast panels and was impressed with the efficient panel installation.
“We wanted to take it a step further with this project and see if we could deliver a full-finished wall, inside to outside,” LMN partner Stephen Van Dyck said.
Thin-brick embedded precast panels also provided ample opportunity for creating a unique exterior design, plus precast was less expensive overall than traditional brick.
Another advantage thin-brick embedded precast panels offered was a safer installation. An existing utility tunnel ran underneath the footprint of the proposed building. Rather than move it, the design-build team opted to design around it, creating a long, flat elevation, adjacent to the tunnel. A traditional brick installation would have called for scaffolding and other equipment on a job site with spatial constraints.
“From a construction standpoint, we looked at what makes sense as far as installation, material availability and how it fit with the overall budget,” Marsh said. “Precast is quick and easy to install. That’s a benefit in this region, where you get a lot of snow and very cold winters.”
As part of the design process, LMN created initial panel mock-ups to prove the concept was doable.
“We are architects who like to get our hands dirty,” Van Dyck said. “We’re interested in what materials can do and how technology can influence that. At the end of the day, it gives us different and exciting results and helps us push the envelope of what is possible.”
Now, it was up to Redmond, Wash.-based Olympian Precast to execute the plan.
In addition to the 460 thin-brick, insulated precast panels, the project called for 120 precast stair treads and landings. Olympian manufactured 217 patterned panels and 243 that were flat. The largest panels measure 26 feet by 8 feet and weigh 8 tons. A typical panel was about 16-feet-tall and 4-1/2 tons.
To create LMN’s unique design in the patterned panels, embedded thin brick was placed at full tilt – out-of-plane by one-and-a-half inches – at the bottom of the panels. Some bricks tilted left to right and others right to left. Each column, which consisted of three to four panels, featured two bell-curve transitions from full tilt at the bottom edge to flat brick at the top edge.
“We’ve never seen anything like it,” said Mike Yore, senior project manager for Olympian Precast. “We spent about six months working out how we were going to make that vision work. There were so many things to consider.”
The bell-curve transitions presented the biggest fabrication challenge, requiring the concrete be cast on urethane liners. And the plastic formliner, which Olympian used everywhere else, needed a rigid backing to support the weight of the concrete and the brick. In addition, the panels came in three widths – ranging from 8 feet wide to 3-feet, 4-inches. In all, the job required 16 different liner sizes, which were supplied by Broomfield, Colo.-based Innovative Brick Systems. The initial backing setup was like “building a puzzle.”
“I don’t think we’ve run into anything this complicated and so unique before,” Yore said. “We could not have completed the job without working with Innovative Brick Systems.”
The insulation system also proved challenging. The 3-inch-thick insulation needed to be reduced in the areas around the windows and the connectors. Cutting the insulation to fit was more than Olympian was prepared to do in-house. Thermomass out of Boone, Iowa, manufactured all insulation sheets to size, labeled them and delivered them as needed.
Ready to Roll
Olympian tried several mix designs before getting the look they wanted. The self-consolidating concrete mix is different than their standard design with less coarse aggregate and increased fine aggregate. The panels feature a 3-and-a-half-inch face, and 3 inches of concrete form the back of the panel, which serves as the interior wall.
“We wanted to add a new sensibility to the interior,” Van Dyck said. “Exposed concrete in an office space was unexpected and unconventional.”
Since the patterned panels weren’t flat, Olympian developed special foam insulation strips to protect the panels for the nearly six-hour journey to the job site.
It was a slick handover. Olympian’s truck dropped the loaded trailer at the staging area, picked up an empty trailer and returned to the plant. When Skanska was ready for panels, workers hitched a truck to the trailer and hauled it to the logistics area.
“We were never holding them up, and they weren’t holding us up,” Yore said.
Full speed ahead
Based on the configuration of the building, Skanska used a mobile crane, versus a tower crane, to pick and place the panels.
It was all straightforward with a few exceptions. The 25 panels that made up the “spine” connecting the Plant Science building to the existing Biotech building were challenging to place.
“Not only were they large, but we had to pick them and swing them into very tight locations next to the existing building,” Marsh said.
In addition, the small, flat panels above and below the windows were offset and connected to adjacent panels rather than to the slab. Skanska installed 15 panels per day on average. Instead of the six months a standard brick installation would have required, Skanska installed the precast panels in 30 days.
“Being able to install the exterior cladding as quickly as possible was a big benefit,” Marsh said. “Pullman gets a lot of snow.”
The Plant Sciences project showcases what can be achieved when the client is open to exploring alternative construction methods and the team works hand-in-hand from the beginning. Everyone involved with the project is proud of the end result.
“This project went well from all aspects – the design, the installation and the budgeting,” Marsh said.
The project may be complete, but the knowledge and growth the partners gained and the relationships built will continue.
“There’s a lot of pride in being able to innovate in collaboration with others, to take a challenging path and find a way to solve those challenges,” Van Dyck said.
Shari Held is an Indianapolis-based freelance writer who has covered the construction industry for more than 10 years.