Precast panels in a lighter-weight assembly are winning converts.
Architectural precast panels have been a go-to cladding material for decades in the hospitality industry. With their design versatility and modularity, the panels offer advantages for architects and contractors. However, precast also can pose some challenges–notably, in its weight. SlenderWall, from Easi-Set Worldwide, Midland, VA, is an alternative that incorporates precast design flexibility into a lighter-weight assembly that also includes a vapor barrier, insulation, and interior-framing studs. The product’s installation advantages are winning new converts among hotel developers, including the team behind the recently completed Holiday Inn located on the campus of Cleveland Clinic in Cleveland, OH.
Cleveland Clinic is a world-class research and clinical-care institution, with more than 40 buildings (including a hospital with more than 1,400 beds) across its 165-acre grounds. Patients and their families come to the facility from across the United States and around the world for treatment. The need for nearby lodging to serve these visitors became obvious when the Clinic chose to demolish a former guesthouse to make way for a new medical-education complex.
The local firm of Kaczmar Architects Inc. (KAI) landed the design contract for the 276-room hotel, operated under the Holiday Inn brand that was intended to take the place of the guesthouse. The firm’s first task was ensuring its plans meshed with Cleveland Clinic’s well-defined architectural guidelines. KAI was not a newcomer to the requirements–as architects for several other recent projects on the campus, they were very familiar with their client’s fit-and-finish priorities.
“White everything,” is the shorthand Dave Kaplan, project manager for work on the hotel’s exterior façade and detailing, used to describe the guidelines. He added that modernist touches, such as incorporating glass curtainwall and wood interior-trim detailing, could be used. “They have a very simple color palette that we have to adhere to.”
KAI architects have frequently used traditional architectural precast panels as exterior cladding for other hospitality projects, as well as other projects on the clinic’s grounds. Initially, Kaplan and his team focused on traditional material for the nine-story hotel. When the building team, which also included contractor Walsh Construction, Chicago, began pricing installation, including the large cranes required to lift the precast panels to eight-story heights, it became very clear an alternative solution was needed.
Representatives from Walsh Construction had worked successfully with SlenderWall on previous projects and suggested that Kaplan take a look at the product. He quickly saw opportunities for budget savings without compromising the design, given SlenderWall’s significantly lighter weight and faster installation time. Because the panels combine multiple building elements into a single system, their use could shorten the project’s overall construction schedule significantly.
“The initial reaction was, ‘What’s the catch?’” he said, remembering some initial skepticism from the building team. “Then we soon realized there was no catch.”
Designed for performance
The outer face of a SlenderWall panel is 2-in. of architectural precast concrete containing polyvinyl alcohol (PVA) fibers and welded-wire reinforcement. Stainless-steel fasteners attach the exterior concrete face to 14- and 16-gauge, G90 galvanized-steel studs in a way that creates a thermal air gap that is filled with factory-applied, closed-cell foam insulation. Even with the addition of the vapor barrier, insulation, and framing studs, the entire assembly is one-third the weight of traditional 6-in.-thick architectural precast. Especially appealing to owners and construction managers is the fact that any potential exterior wall problems can be addressed through a single point of contact.
“It’s essentially a one-phone-call product, because a SlenderWall panel contains the framing studs, the insulation, and the precast,” Kaplan said. This differs from traditional precast construction, with different manufacturers and installation crews handling each of the building-envelope elements. In such projects, he said, “If something happens in the future, everyone’s pointing fingers.”
The SlenderWall-producer’s team at Smith-Midland, Midland, VA, was very responsive to all his questions, providing design details in graphic formats compatible with KAI’s Revit platform, and lending assistance on such safety-related issues as the appropriate means for fire stopping the gap between the edge of the floor slab and the back of the precast panel. (SlenderWall is manufactured by a network of architectural precast concrete firms through licensing agreements with Easi-Set Worldwide.)
“They were able to point me to UL assemblies they’ve used on other projects–they were able to answer all my questions, and they provided the graphics,” he said.
As KAI’s plans moved from CAD screen to the construction site, the process of installing the 31,467 sq. ft. of SlenderWall panels proved just as smooth as their design, according to Kaplan. One concern had been pairing the traditional architectural precast used at ground level with the new panels used to clad the floors above. Because the 10,252 sq. ft. of precast was also fabricated by Smith-Midland, the acid-washed finish was a perfect match between the two materials. Erection proceeded on time and on budget, with no complications for the Walsh Construction team.
“I can’t think of any hiccups, and I can’t think of anything I’d want to change,” said Kaplan, who said he’d be coming back to SlenderWall for future projects, thanks to this experience. “Any time you can just watch things go up as you expect, that works for me.”