Sound of the City
The sound quality of the Winspear Opera House has been receiving rave reviews. At least that’s what Billy Hubbard, general manager with DMG Plaster & Stucco Inc. says of this newly opened facility, located in Dallas.
The Margot and Bill Winspear Opera House is a new opera house which forms part of the AT&T Performing Arts Center, located in the Arts District of Dallas. It is one of four venues comprised by the AT&T Center and was dedicated last October.
The project was designed by Foster + Partners (principal architect was Spencer de Greey). At this year’s Texas Lathing and Plastering Contractors Association 10th Annual Design Awards, it won best interior commercial plastering project.
The opera house was made possible in part by a $42-million gift from the Winspears. The London firm Sound Space Design (principal acoustician was Robert Essert) developed the acoustical design of the opera house and the acoustics have been engineered specifically for performances of opera and musical theater. The stages are also equipped with appropriate flooring for performances of ballet and other forms of dance.
The Winspear Opera House is the new home of The Dallas Opera, which until the 2008/2009 season performed at the Music Hall at Fair Park, and the Texas Ballet Theater.
The Winspear Opera House includes the Nancy Hamon Education and Recital Hall, a space that can be used for smaller performances seating audiences up to 200, as well as classes, rehearsals, meetings and other events.
General contractor Linbeck, of Houston, commissioned DMG Plaster & Stucco to frame, lath and plaster the project from its Ft. Worth branch. Hubbard says the contractors didn’t believe that DMG’s construction schedule could be completed in four months. If it wasn’t for other construction snags that DMG had no control of, that schedule may have been possible yet still the company was able to do the work in six months.
The scope of work for DMG was to install a suspended 14,200 square foot auditorium plaster ceiling. Not just a traditional suspended plaster ceiling, the designer required 2 inches of plaster on the ceiling. It was also not just a flat ceiling but included a large tilted dome; in addition there was 21,000 square feet of plaster over masonry and 32,400 square feet of veneer plaster. “The job was large and a definite challenge, but we were up for it,” Hubbard says.
The auditorium ceiling required a suspension system that could support the weight of 2-inch thick plaster and some additional design considerations where in order. Two inches of plaster is a definite challenge and few, if any, plaster experts would apply that much plaster to a traditionally framed suspended cold rolled channel (CRC) suspension system.
“The initial challenge was meeting the acoustician’s requirement for a full 2 inches of plaster,” says Hubbard. “We knew it is not advisable to have a 2 inch plaster ceiling on a single layer of lath.”
For the suspended ceiling to carry 2 inches of plaster, everything had to be “beefed” up. The 9 gauge hanger wires supporting 2-inch main channels (CRC) were moved from 48 inch spacing to 36 inch spacing. The cross furring was a stout 1½ inch channel spaced 13½ inches on center. The first layer of metal lath (3.4 psy) was wire tied to the 1½ inch furring channels. Another row of more traditional ¾ inch CRC furring was wire tied to the 1½ CRC sandwiching the metal lath. A basecoat of Structobase gypsum plaster was applied to the lath and the ¾ inch CRC furring was used as grounds for plastering. A second layer of metal lath (3.4 psy) was applied over the Structobase and attached with wafer head screws to the ¾ inch CRC furring. A full inch of Structobase was applied over the lath to meet the acoustical requirements required. A veneer finish plaster was applied with a fine sand finish.
“We thought about the old school 2-inch studless plaster partitions made of CRC with metal lath on both sides, and decided this principle could work on a suspended ceiling, and with a little improvisation, it worked perfectly,” says Hubbard.
To add to the complexity, the ceiling has a large offset center dome tilted toward the stage. The angles and radius were calculated for optimum acoustical performance and there was no room for forgiveness or error.
There are three independent radius ceiling tiers surrounding the large dome. The three radius tiers were individually separated by 24 two-inch wide aluminum reveals that had to align perfectly with side wall light pockets.
“The 24 reveals resemble wheel spokes that come out and making them align perfectly with the masonry light pockets was no easy task,” Hubbard says. The resulting effect was to create 55 individual radius ceilings. The reveals ultimately go down five floors all the way to the basement.
“To us, it resembled a giant peeled orange,” Hubbard continues. “It was a layout nightmare, but rewarding in the end.”
LIGHT IT UP
As if the challenge of the ceiling was not enough, a $3.9 million chandelier with retractable lights was designed to be installed in the center of the dome. The chandelier required 311 pipes from the chandelier through the plaster to the power platform above.
“We had to work closely with the lighting company to insure no hangers and framing would interfere with the pipes. The pipes had to align perfectly for the retractable lights to function properly and fortunately, the retractable lights work perfectly,” says Hubbard.
Additional work included the five levels of perimeter masonry walls of the auditorium which received a full 1 inch of Structobase plaster with a Dryvit Freestyle finish. There were also corridor walls that go around the entire auditorium feeding the five levels; these received a premium Kal-Kote veneer plaster by National Gypsum.
With the architect’s eye for design, acoustician’s knowledge of sound, some old-fashioned ingenuity from the contractor and quality products, the project turned out to be a huge success. So, if you find yourself in Dallas, visit the opera house, lend your ear, and maybe just look up at the ceiling too, because all the art is not just on the stage. W&C