Most mass timber projects are some kind of hybrid, boasting steel or concrete lateral systems, but Cincinnati Public Radio's (CPR) new $32 million headquarters in Evanston is something of an anomaly.
The 35,000-square-foot structure's lateral system is comprised of cross-laminated timber (CLT) load-bearing walls, creating a building with a superstructure comprised almost entirely of mass timber, Skanska said. Dean Lewis, Director of Timber and Prefab, explains. Construction manager.
“The entire post-and-beam structure, second floor, roof structure, and some internal load-bearing walls and perimeter walls are made of mass timber,” he says.
When completed in early 2025, CPR's new home of 88.5 WMUB, 90.9 WGUC and 91.7 WVXU will be the first two-story bulk timber building in both Cincinnati and the Midwest region.
Almost the entire project is constructed of mass timber, including internal shear walls and some of the perimeter walls.
Photo courtesy of Skanska
Mass timber not only functioned as a sustainable resource, but also leaned into the owners' desire for an iconic building that would be recognized, welcomed, and adaptable. However, given that mass timber systems differ from the common choices of concrete and steel, the design team worked carefully to find the optimal structural bays, said Adam, senior project architect at emersion DESIGN. – Luginbill explains. This allowed the team to maximize the potential of his CLT panels, minimizing both the size and amount of beams required while keeping the panels at the appropriate thickness.
The 35,000 square foot facility, delivered under a CMAR and GMP contract, features two on-air studios (two more for interviews and one for performance) and 11,000 square feet of office space. A freely available podcast booth will allow anyone in the community to record their own content, and an outdoor gathering and performance area will offer a variety of programs, including concerts, educational programs, and receptions.
Planning began in 2018, with emersion DESIGN and Skanska already on board, but the COVID-19 pandemic disrupted CPR's fundraising efforts.
“As a nonprofit organization, CPR needed to find funding to construct the building, the largest project in the station's history,” said Richard Eisworth, CPR president, general manager and CEO. I will explain. This effort is also the first traditional capital campaign in CPR's more than 60-year history.
The owners considered more than 20 sites and the possibility of building foundations or renovating existing spaces, but decided to locate the station in a diverse and growing Evanston area where CPR could invest and give back. says Eisworth.
The site, which was previously a parking lot, is also adjacent to Evanston Park, a public space where the station plans to host concerts and other events.
“This building is designed to feel integrated and complementary to this public space,” says Nikki Goldstein, design architect at emergence DESIGN. “Visually, it is a simple pavilion with transparent exterior walls. However, the construction of a seemingly simple building is often a complex undertaking. The execution of the glass walls and exposed structure is crucial to its success. It’s important: there is no place to hide flaws in a simple structure.”
Temporary protection was installed on all columns from the slab to 8 feet above the ground to protect the large interior wood elements.
Photo courtesy of Skanska
Rapid rise
Since construction began in September 2023, construction has progressed rapidly. Construction of the building began in November, and after just 34 working days, Skanska workers installed 498 panels consisting of shear walls, wall and floor panels, columns, beams, and roof panels, with the last roof panel It was installed on December 22nd.
The large quantities of wood arrive pre-assembled and delivered using 28 trucks, necessitating extensive coordination before production can begin. Jeff Smoker, Skanska's project manager, explains that early involvement and a partnership with bulk timber manufacturer Nordic Structures helped the CPR project secure production slots on schedule.
“As a nonprofit organization, CPR needed to come up with the funds to construct the building, which is the largest project in the station's history.”
—Richard Eisworth, President, General Manager and CEO of Cincinnati Public Radio
From there, BIM coordination served as a key tool to ensure both timber assembly and system installation proceeded smoothly.
Although the structure has reached its top, many of the building's interior mass timber elements remain exposed, making it difficult to preserve these structures while work progresses here and there. It's clear.
“Skanska quickly installed the roof and purchased a complete RWES. [reusable weather enclosure system] It was used on the exterior of the building to minimize the impact of moisture on the final product,” said Skanska Director Dustin Hopkins. “Due to the finished wood, the construction team had to do a lot of work differently. Work such as layout and material cutting stations all had to be properly adjusted to protect the wood. . Temporary protection was also installed on all columns from the slab to a height of 8 feet above the ground.”
As an alternative to traditional reinforced plastic wall systems that are discarded at the end of a project, RWES “installs more quickly, performs better in high winds and rain, and can be folded and sent to the next project. ” he said. Say. “This product can also be cut to custom sizes for pitched roof applications such as CPR, or customized for skin or curtain wall installations.”
Cincinnati Public Radio's headquarters will look like a simple pavilion with transparent exterior walls, but recording facilities will be housed inside the environmentally friendly building.
Rendering provided by: emergence DESIGN
healthy and sustainable
Balancing the building's functionality and iconic design was another challenge. “It would have been very easy to leave the acoustics as they were and lose the original beauty of the building,” Hopkins said. “However, we were able to create a beautiful finished building while still meeting the acoustical requirements of the studio.”
The facility's studios are designed with solid CLT walls, and each studio is acoustically isolated with a box-in-a-box design. Meanwhile, the floor has an acoustic slab floating on top of the structural slab. Neither the framed walls nor the ceiling touched the building structure, and all penetrations were sealed as well.
“Where there are windows, in addition to the exterior glass, there is a layer of 1-inch-thick laminated glass on the separated interior walls,” Luginbill says.
During the design, architectural acoustics consultants WSDG actually recorded traffic noise from the site to simulate how it would sound in both the studio and conference room adjacent to the street, he says.
“Radiant heating and cooling means we can largely eliminate ductwork from areas of exposed structure.”
—Adam Luginbill, senior project architect, emergence DESIGN
Sustainability and occupant health were also owner-driven priorities, with LEED Gold goals set early in the design process.
“In addition to specifying low-emission materials, indoor air quality testing will be conducted upon completion of construction. The use of natural materials, primarily exposed solid wood, and daylighting are intended to improve occupant well-being. ,” says Luginbill.
The pillar lattice is exposed, in line with the design, which aims to emphasize the building's very structure. But wherever there are partitions, they are pulled back from the columns, so the structure remains visible, Goldstein says. The staircase was also strategically placed to showcase his CLT load-bearing walls. On the second floor, the closed glass space was removed to create an open office environment.
However, integrating building systems within such a confined, confined space required careful management and a bit of creativity.
“The design team concentrated the ductwork, piping, and cable trays in the center of the building, ensuring that there were as few visual obstructions as possible from surrounding areas where the structure was exposed,” Luginbill said, adding that within the exposed areas He added that all systems are unnecessary. It was kept as discreet as possible.
But as with the building's HVAC system, which uses radiant heating and cooling, proposed by MEP engineer CMTA, these constraints were also irritating.
“Since the program required acoustic control, the design team recognized that this meant a tight envelope, allowing for tight control of humidity within the building,” Luginbill adds. “Radiant heating and cooling allowed us to significantly eliminate ductwork from areas of exposed structure, and its energy efficiency contributed to our sustainability goals.”
In fact, the only duct in the building is for outdoor air supply and exhaust only and is hidden in the heart of the building. This system also helps eliminate recirculated air and improve air quality for occupants. When the building is completed next year, residents will have access to the facility's recording space and support programs.
Meanwhile, the crew is nearing the halfway point of the project as of mid-March, having already logged 17,500 trading hours and zero recordable.
