Drywall Grid System Used in New Public Library
February 2005The new main branch of the Salt Lake City Public Library houses more than half a million books. It also houses a number of features not often found in a traditional library. They include everything from cozy cafes to spiraling staircases.
Designed by the internationally known architectural firm of Moshe Safdie and Associates, the new 240,000-square-foot facility houses a number of non-traditional architectural features as well. Included among them is a 4,000-square-foot, free-floating, undulating drywall ceiling that dominates a circular 300-seat auditorium.
The ceiling is unique not only because of its stunning visual, but also because of the method used to frame it out. Instead of traditional hat track and carrying channel, a drywall grid system was used. The result was a complex ceiling that was framed in half the time as more conventional construction methods.
Auditorium Ceiling Has Potato Chip Contour
Spacecon West, a Salt Lake City contracting firm that provides metal stud framing, drywall installation, acoustical ceiling installation and variety of other services, installed the ceiling in the auditorium as well as the ceilings in many other spaces throughout the facility.
Gary Hatch, the project superintendent on the job, explains that in order to obtain the desired acoustics in the auditorium, the architects designed an undulating drywall ceiling profile that his crews nicknamed the "potato chip." He notes the ceiling installation was difficult because of the need to follow the unusual contour: "Making things even more difficult was the fact that it was not one continuous ceiling. It was comprised of seven individual sections of varying widths and lengths separated by a 6- to 12-inch gap between them. There is also a gap around the perimeter of the room, so the outside edge of the ceiling never touches the wall. As a result, we had to suspend the entire ceiling."
The ceiling sections run parallel to each other like wind-blown ribbons from the back of the auditorium to the front. And, because the space is circular, the lengths of the sections differ, ranging from about 30 feet on the ends to nearly 150 feet in the middle.
Drywall Grid System Simplifies Curves
When it came to framing the unusual ceiling, Hatch notes that the firm originally considered using the traditional method of cold rolled steel carrying channels and hat tracks. But then, he began thinking about the possibility of a drywall grid system instead. "We had used the Armstrong Drywall Grid System before and were impressed with the speed with which it goes up and the ease with which curves are created," he says.
The lightweight system is suspended from above using hanger wires like an acoustical ceiling grid system. Its main beams and cross tees have a wide one and a half-inch knurled face that allows easy installation of screw-applied gypsum wallboard by reducing screw skate. They also are rotary-stitched, providing extra torsional strength and stability by reducing twisting of the components when the screws are attached.
"Since we had some limited experience with the drywall grid system and a lot of experience with acoustical ceilings, it just made sense to investigate this alternative. We eventually decided it was a good idea, and now we're really glad we tried it," Hatch says.
Hatch notes that his previous experience with drywall grid was with barrel vaults, where the radii of the curved elements were all identical. "I had never been involved in a drywall grid project where we had to follow a contour as intricate as this and where so many different radii had to be formed. However, everything worked well," he says.
According to Hatch, the ability to pre-form the curved main beams on the ground was key. "Once we created the curves, it was just a matter of snapping the components together," he notes. "Compared to track and channel methods, the drywall grid system was at least 50 percent faster."
Not only was Hatch impressed with the speed of installation, but also with the speed with which the crews learned the installation process. "Many of the technicians on this job were very experienced framers," he says. "And, there is sometimes a tendency by journeymen to resist change because it feels like they're apprentices again. But once they were taught the tricks of the trade, they all saw the benefits of the system and became very proficient at its installation in a very short amount of time."
Undulating Ceiling Duplicated in Lobby
The same undulating ceiling visual in the auditorium is duplicated in the lobby located outside a series of small meeting rooms. "The architects wanted the same look so that when people attending a large general session in the auditorium broke up into smaller groups in the meeting rooms, there would be some continuity in the spaces."
Hatch notes that this ceiling is much smaller in scale, with the parallel ribbon sections running only about 30 feet in length rather than 150 feet. But, framing the ceiling was once again complicated mainly because the lobby is crescent shaped.
"If it were rectangular, it would have been much easier," he says. "However, the drywall grid system once again made the installation much quicker. As in the case of the auditorium, we could have used conventional track and channel construction here, but it would have been a lot harder and taken a lot longer."
System Used for Exterior Stucco Ceiling
The drywall grid system was used in exterior applications as well, including a long stucco ceiling located under a walkway that leads to a roof garden. "Once again, we could have used cold rolled steel and hat track to frame it out," Hatch says, "which is what the stucco contractor expected because it was the traditional way of doing it. However, we used the drywall grid system again because it was much easier. "As far as the finished job was concerned, the stucco crews couldn't tell which framing method was used, traditional or drywall grid," he continues. "As long as we gave them a good, sound base on which to attach their stucco, they were fine. So, while it may not have made any difference to them, it made a big difference to us because the drywall grid system went up a lot quicker."
Speed, Versatility Are Biggest Benefits
In total, nearly 51,000 square feet of drywall ceilings were installed on a drywall grid system throughout the interior and exterior of the facility.
Reflecting on the entire project, Hatch describes it as "one of our toughest, if not the toughest, jobs ever. From the installation of the 'potato chip' ceiling in the auditorium to the installation of the football-shaped ceiling that soars five floors above the children's section, the library was a challenge. However, now that it's completed, it's one of our crown jewels."
About the Author
Dave Lewandowski is a free-lance writer based in Philadelphia who specializes in writing for the construction industry.