The $8.2 million Performing Arts Center for Westlake City Schools, Westlake, Ohio, stands proudly next to Westlake High School. The building boasts a full-service television studio, 825-seat auditorium, rehearsal room and dressing rooms, among other things.
As people sit in this brand-new facility watching plays or listening to orchestras, they may look up and admire the building's high, acoustically designed ceilings, but they won't realize the hours of planning and research that went into its roof system.
From the beginning, the architectural firm chosen to design the building—Westlake, Reed, Leskosky Architects, Cleveland—tossed around ideas for the building and pondered their applicability. The firm enlisted the help and advice of a longtime contact—NRCA member West Roofing Systems Inc., LaGrange, Ohio—that had worked with the firm for more than 20 years.
"They contacted us during the preliminary design stage to discuss the applicability of the unique details they were designing and ensure the details could be installed in the field, as well as perform long-term," says Jack Moore, project engineer for West Roofing Systems. "During the design of the project, we discussed and reviewed different details and construction methods to develop a unique project application and obviously bid the project."
The unique project application was a robotically installed spray polyurethane foam (SPF) roof system.
A work of art
There were seven roof areas and elevations spread out over the 40,000-square-foot (3716-m²) building, which Moore says created an uncommon building footprint because many of the walls were curved or arced, creating unique sloping patterns to provide the 1/4-in-12 (1.2-degree) slope. Other walls did not provide 90-degree angles and were built on tangent angles, which created difficult drainage patterns.
To begin the roof system installation, the company mechanically fastened 1/2-inch- (13-mm-) thick Dens Deck to the metal roof deck. It then installed 4 1/2-inch- (114-mm-) thick BASF Elastospray 5100 spray polyurethane foam using auto-slope robotic technology.
"The robot is equipped with a programmable logic controller (PLC) that calculates the three input variables—SPF thickness at the start; SPF thickness at the end of the pass; and the distance to travel," Moore explains. "The PLC will change the robot's rate of speed every 2 inches (51 mm) of distance traveled, creating a perfect taper."
Moore says another benefit of the robotic technology is that when the programmed distance is reached, an alarm alerts the foam mechanic to either begin another pass or invert the original program. So if the building or drainage pattern is symmetrical, the robot will continue to invert the original program—beginning at 1 inch (25 mm) thick, traveling 50 linear feet (15 m) and finishing at 2 1/2 inches (64 mm) thick; it then inverts and travels another 50 linear feet (15 m), finishing at 1 inch (25 mm) thick.
"Using auto-slope robotic technology, we were able to achieve the 1/4-in-12 (1.2-degree) slope that was specified," Moore says. "This technology allowed us to program specific thicknesses of the SPF at the high point and low point over varying distances. Certain roof areas required multiple passes of this nature because the SPF thickness exceeded 7 1/2 inches (191 mm) at some high points."
The specified SPF protective coating was BASF Elastocoat 3-5000 silicone roof coating, and the total coating thickness was 40 mils (0.04 inches [1 mm]).
"The coating was installed in three separate and distinct layers," Moore says. "The base coat was dark gray; the intermediate coat was light gray; and the top coat was white with 3M white ceramic granules installed at a rate of 50 pounds per square (2441 g/m²), providing an ENERGY STAR®-qualified roof surfacing."
In addition to the SPF roof system, West Roofing Systems also installed a custom perimeter metal fascia system.
"The metal fascia system was unique in several ways," Moore says. "Instead of a typical coping system that generally is installed in this type of wall assembly, we installed Metal-Era Inc.'s 0.080-inch- (2-mm-) thick aluminum fascia system, allowing us to carry the roof system up the parapet and across the top of the wall to the outside edge of the building. This eliminated the need for additional conventional counterflashings and termination details and provided cost savings and 100 percent waterproofing of the parapet wall.
"The fascia system also required custom post-coat finishing in four colors to match the custom colors of the insulated wall panel system," Moore continues. "In addition, because of the unique style of the wall construction, six custom profiles were necessary to accommodate the varying wall conditions."
Staying on schedule
Scheduling issues with different trades posed a challenge because specific areas of the building needed to be dried in so the finish trades interior crew could remain on schedule.
"Many of these areas were not completely ready for the roof installation," Moore says. "The challenge was to provide as much dry space without being able to install the roof to the top of the walls because some exterior walls were not completed or ready for the edge metal system. We had to provide temporary means—sheet metal to bridge openings and SPF to seal joints, splices and gaps—to divert the flow of water until the exterior walls were complete."
Using auto-slope robotic technology to install the custom-tapered roof assembly also was challenging. Curved walls with 96-foot radii draining to through-wall scuppers created unique tapering patterns. In addition, obstructions made the project difficult at times with a concentration of heating, ventilating and air-conditioning (HVAC) equipment in a 4,000-square-foot (372-m²) area that had six large units and 29 6-foot- (2-m-) long equipment rails spaced an average of 6 feet (2 m) apart.
"All the HVAC equipment was rooftop-mounted and required a maze of equipment rails to support all the associated duct work," Moore says. "This added to the complexity of installing the tapered roof assembly while much of the ancillary rooftop equipment obstructed the flow of the drainage."
The company paid close attention to safety, using standard perimeter warning-line stanchions, warning lines and lifelines and harnesses beyond the 6-foot (2-m) warning line—tie-off points were made part of the structure during construction.
"Man lifts were used to access the 70-foot- (21-m-) high roof area," Moore says. "Harnesses and lanyards were used in the man lift, and point-of-access barricades were used on the roof. Lifelines were attached to the tie-off points that were part of the structure at the roof access point."
The confidence placed in West Roofing Systems for the highly visible project was important for the company.
"The Westlake Performing Arts Center was a high-profile project within the community and a major investment from the school district," Moore says. "To have so many entities—the school district and architects, among others—have faith in the BASF SPF roof system and West Roofing Systems proves we truly provide a valuable service and are well-received in the construction industry."
Krista Reisdorf is associate editor of Professional Roofing magazine.
Westlake City Schools—Performing Arts Center
Aug. 9, 2004-Sept. 27, 2004
Roof system type:
Spray polyurethane foam
West Roofing Systems Inc., LaGrange, Ohio
BASF Corp., Hudson Falls, N.J.
Westlake, Reed, Leskosky Architects, Cleveland