Crystal Bridges Museum Store Ceiling Soars
The opportunity to participate in the building of a unique, high-profile, world-class art museum in Bentonville, Arkansas was thrilling – but presented enormous challenges. The Crystal Bridges Museum store is as stunning as it is unique, and a tribute to quality materials, superb workmanship and outstanding team effort.
Crystal Bridges Museum is a world-class art museum nestled in the heart of the Arkansas Ozarks. The museum houses a priceless collection of American masterworks spanning five centuries from the Colonial era to the present day. Established by Alice Walton, daughter of Wal-Mart founder Sam Walton, the museum's permanent collection is augmented by ongoing temporary exhibitions all displayed in a series of buildings designed by the internationally acclaimed architect Moshe Safdie. In addition to galleries, the Museum complex includes a library, an art studio, a glass-enclosed lecture hall, a restaurant, areas for outdoor concerts and public events, and 120 acres honeycombed with walking and biking trails. The museum store offers mementoes inspired by the permanent collection, prints of many of its most popular works, and original works by some of the finest artists and artisans in the region.
The interior of the museum store, designed by local Arkansas architect Marlon Blackwell, retains and extends the museum experience with a stunning ceiling profile made up of 225 parallel segments, each of a different length, sweeping around a circular radius. This series of parallel cherry plywood ribs organizes the store and forms the ceiling and millwork on the rear wall. The surface undulates to create an elegant sectional profile extending across the ceiling and down the back wall, ending in a series of curved drawers that follow the curved walls. The finished design of the museum store has been likened to the ribbed underside of a mushroom known as a lamella, with the ribs creating visual movement along the surface.
Blackwell was candid about the origin of the unusual design concept: "The first thing was to resolve the issues of a white box area, a west-facing store front and a vast curved interior space," he said. He opted to resolve the dilemma by working with the curve.
Blackwell also sought to integrate the surrounding Ozark habitat as well as local cultural conventions, material logic and craft traditions into the store's design. In particular, he was inspired by the work of Leon Niehaus, a Huntsville, Arkansas-based basket-maker and one of the featured artists in the museum.
Emulating a motif Niehaus uses in some of his baskets, Blackwell developed a profile made of plywood ribs extending the entire length of the store's space, and then extruded the ribcage along the curve. The effect resembles the underside of a mushroom but instead of lines radiating out from a center point as in a natural mushroom, the lines are straight.
The lamella goes across the ceiling and down the back wall giving way to a series of 26 curved drawers that follow the curved walls. The drawers are parallel with the lamella so essentially each drawer is a parallelogram with a curved front.
"This treatment resolved the issues with the curved space and fit like a glove," according to Blackwell. The design is very practical, filtering out about 40% of the light, providing uniform shade from the western sun, and creating a smooth, seamless envelope. The ribs also screen the mechanical systems behind them, including the electrical, sprinklers and lighting systems, and complement the merchandise in the museum store.
It was Adam Weaver of UDI, Inc., an architectural millwork company in Rogers, Arkansas, who brought Blackwell's vision to life. "He [Blackwell] approached us to see if the concept of a curved room modeled after the underside of a mushroom was possible," said Weaver.
"It's a tricky design because the contour sweeps around a radium and the panels are all parallel so no two panels are the same. It had never been done before, but we knew it was feasible."
Blackwell selected native woods for the execution of his vision: cherry plywood for the canopy, back wall and floor; walnut for the cash wrap, freestanding gondolas and other fixtures within the envelope.
Weaver determined that each of the 225 ceiling segments would be made with eight-foot-long pieces of plywood connected together to span up to 40 feet in length. He chose cherry plywood with j-core to minimize voids. Since the plywood would be seen on both sides, he specified AA grade – virtually flawless on both sides. Because of the highly machined construction process, the inner plies of the panels also had to be 100% solid, with no nicks, knots or imperfections whatsoever. In addition, the materials were specified to be environmentally friendly, SFI-sourced and with no-added urea formaldehyde plywood.
With the Museum's opening gala just seven weeks away, it was up to the architectural and construction teams and the suppliers to bring this exceedingly complex, high-profile job in on time. Fortunately BlueLinx was able to fulfill the material requisition and provide 480 4' x 8' sheets of Timber Products' GreenT Hardwood Plywood within four weeks.
"The job called for a very high standard," said Roger Rutan, vice president of marketing for Timber Products. "Both sides of the panels had to be perfect. We used a rigorous QC process so that absolutely no shop panels were sent."
Next came the tremendous challenge of constructing the ceiling ribs and other fixtures within the store envelope. UDI, Inc. put the custom plywood sheets through the CNC routing process, manufactured the joints for the wood and joined the pieces.
The ribs were fabricated from four pieces of wood, but each segment has the appearance of one solid piece so the wood grains had to be carefully aligned. Every rib is unique and had to be individually customized due to the curvature of the space. Lights and storage compartments were also embedded within the ribs.
The joints were critical, both in terms of appearance and strength, and the team weighed various options for connecting the pieces. After considering tongue and groove, blind joint and half lap joints, Weaver and his team chose half laps as the strongest joint. Since some of the joints were fixed in the ceiling while others needed to be removable to allow access to the mechanical systems above, blind fasteners were put through the half laps in the removable joints. The architect was adamant that all joints line up in every other section so the joints were strategically placed to be subtle and to follow the curve of the room.
The programming was done using an AlphaCAM CAD/CAM program. "This was the most challenging and time consuming part of the job," Weaver remarked. "Once we received the drawings of each section from the architectural team, we had to determine where every joint should be and align the grains. Each rib is different, varying by anywhere from .04" to 1.5" depending upon its placement in the curved room. We learned to program quickly and efficiently, and coordinated the process extremely carefully so we didn't miss any pieces."
Then came the routing process. "Due to the tight deadline dictated by the scheduled opening of the museum, we used two routers, an Onsrud CNC router and a Northwood CNC router," said Weaver. "We were able to cut with great precision thanks to the consistency of the plywood from Timber Products."
Each piece was numbered and checked as it came off the router, and then checked again at the time of delivery to be sure no pieces were missing.
The lamella design in the curved envelope called for very intricate machining; yet the team had only two mis-cuts and out of 1,200 joints, just one was incorrect. Here are some of the stats:
- 480 custom plywood panels
- Approximately 1400 cut pieces
- 225 parallel segments
- 1200 assembled joints
- Two mis-cuts and one rejected plywood panel.
"This was truly a testament to the quality of the panels and also the quality of the team," noted Weaver.
"The team was fantastic," he said. "The owner was very supportive and excited about the project. And the suppliers and architectural and construction teams were open to feedback and willing to listen to input. Everyone knew we were on a very tight deadline, and so good communication was really important. As it is, we completed the job on time and on budget."
"For our part, we're proud of the fact that our customers help us get better," said Timber Products' Rutan. "We have an experienced manufacturing team that knows what they are doing, and also a culture that continually seeks to improve. We understand that there is always a tweak – an improvement in documentation, manufacturing, communication – some small refinement we can make to get better."
"These days quality is a given," he adds. "If you're not making a quality product, you're not in the game. You've got to be better than that and better than your competitors. And you've got to have a manufacturing culture that underpins that."
Blackwell also credits the technology that allowed the architectural concept to evolve from a hand crafted origin to a digitally crafted fabrication. "Digital fabrication enabled us to work with a complex curve form in a cost effective way and further extended our work at the intersection of nature-made and man-made," he said.
The Crystal Bridges Museum store has an intensely architectural interior. "We worked with the space architecturally; it is not interior design in the traditional sense. In many ways it defies traditional assumptions about the use of interior design and interior space," Blackwell says.
He adds that the museum store proves that good design means good business. "This store paid for itself in four months. It cost $200 per square foot to build; the total cost was $600,000. And it looks like a million," he says.