As other cities embrace ‘mass timber,’ Chicago remains wary

Wood is having a moment in the world of architecture. Cities such as Milwaukee and Minneapolis are going all-in on an innovative type of wood whose boosters claim takes less energy to produce than concrete or steel. It might even be on the verge of making inroads in Chicago, where the Great Fire of 1871 incinerated vast stretches of the city as it raced from one wood building to another. The type of wood in question is not stick-like two-by-fours. It goes by the catch-all phrase “mass timber,” which encompasses a series of engineered wood products that are laminated, nailed or pressed together like panini to form solid, high-strength wood panels. Typically, mass timber forms the internal structure of a building and is left exposed, recalling old lofts. Exteriors are clad in other steel, glass and other materials. In Milwaukee, developers plan to break ground this spring on a 25-story residential tower that is billed as the world’s tallest mass timber structure. Designed by Milwaukee’s Korb + Associates architects for a local developer, New Land Enterprises, the tower would consist of a six-story concrete parking structure topped by 19 floors of apartments largely built in wood. The exterior would be sheathed in glass. Chicago’s mass timber efforts are modest by comparison. Last week, when Related Midwest announced it will start construction on The 78 megaproject along the Chicago River, the developer’s president, Curt Bailey, hinted that the project’s first phase could include low-rise office buildings supported by mass timber. If Related Midwest proceeds, its mass timber office buildings would stand just south of Chicago’s downtown fire district, a legacy of the Great Fire. Many types of wood construction are prohibited within the district, bordered by Halsted and Division Streets, Lake Michigan and Roosevelt Road. Backers of mass timber, including the wood industry, say it’s strong enough to be a primary structural support, yet, they add, it’s lighter than concrete or steel, allowing foundations to be smaller and less costly. The boosters also claim that the material’s tactile warmth, which is evident when it’s left exposed, appeals to those who have grown tired of cool modernism. And, crucially, they argue, mass timber is noncombustible, meaning that exposed wood columns and beams would char around the edges rather than burst into flames if fire struck. But the biggest reason behind the surging interest in the material may be its perceived environmental benefits, which appeal to architects to trying to fight climate change and to developers and companies eager to market their buildings and brands as green. A prime example: The handsome, energy-saving McDonald’s flagship in Chicago’s River North, which opened in 2018. Designed by Chicago architect Carol Ross Barney, the flagship uses a type of mass timber, known as cross-laminated timber, in addition to its main supporting structure of thin steel columns. “It’s starting to happen all around us, in a lot of other cities,” said Todd Snapp, a Perkins and Will principal whose concept design for an 80-story residential tower on the Chicago River’s south branch explores mass timber’s engineering and aesthetic potential. “That’s where Chicago is right now. The practicality is starting to prove itself out.” In a further sign that mass timber is gaining traction, or at least gaining interest, architects, engineers and other building industry professionals from around the globe jammed a hotel conference room in October when the Chicagobased Council on Tall Buildings and Urban Habitat held a session on mass timber at its 10th World Congress. “I don’t think five years ago we could have packed a room like this,” said one of the speakers, Steve Koehn, director of cooperative forestry for the U.S. Forest Service. He touted mass timber as a way to encourage economic growth in rural areas, clear overcrowded forests and make nearby communities safer from the threat of fire. Changes due to take effect next year in the International Building Code, a model building code, would make it easier to use mass timber if local governments adopt the code’s provisions. The international code will permit mass timber buildings of up to 18 stories. But Chicago’s building code, which was revamped in 2019, barely cracks open the door to the material. The revised Chicago code allows architects and builders to use mass timber, but only in interior construction and only in buildings with a height of no more than six stories or 85 feet. That’s according to Mark Walsh, a principal at the Chicago office of Perkins and Will, who served on a working group that helped city officials update the code. “We are moving toward more expansive use of mass timber, but possibly not as quickly as some other municipalities,” Walsh wrote in an email. Those cities include Minneapolis, where in 2016, the Houston-based developer, Hines, opened a seven-story, 221,000-square-foot office building called T3 (for timber, technology and transit). Designed by Vancouverbased Michael Green Architecture and the Phoenix-based DLR Group, the boxy building is clad in self-weathering Corten steel with an interior that showcases its exposed wood structure. It’s won praise from architecture critics who noted how well it fits in with the century-old structures of the city’s North Loop warehouse district. “It’s hard to imagine a better blend of heritage and contemporary,” Minneapolis writer John Reinan observed in Architecture MN, a magazine of the American Institute of Architects’ Minnesota chapter. But such advances have proved difficult to duplicate in Chicago. In 2017, the Midwest office of Hines floated a plan for a six-story, 270,000-squarefoot office building on Goose Island. Called T3 Goose Island, it was to be built, appropriately, on the site of a shuttered lumber yard. “We’re reacting to demand in the market for unique, authentic office environments,” Brian Atkinson, a Hines managing director, told the Tribune at the time. “Timber has an appearance, texture and smell a warmth to it that you don’t get with concrete and steel.” Three years later, however, Hines has been unable to sign a tenant, so construction has not begun. That’s too bad because Chicago is known worldwide as a laboratory of structural innovation, having played a crucial role in engineering advances that allowed skyscrapers to rise to greater heights. The city is also home to architects, like Snapp, who have helped chart a new course for mass timber. But when it comes to having examples of this latest design trend within its borders, Chicago is a follower, not a leader.