Code changes and cost issues are leading developers to frame mid-rise apartment buildings with wood instead of steel and concrete. Throughout town, apartment complexes up to six or even seven stories are framed with wood. While Ohio code limits wood buildings to 85 feet in height, developers elsewhere are looking to frame far taller buildings with wood.
Many of those apartment buildings going up in central Ohio are adding a new feature to multifamily living: wood construction.
A change in building codes allows apartments built largely of wood to rise six or seven stories high, compared to the more traditional three or four stories.
“It’s the norm now,” said Amit Ghosh, the chief building official with the city of Columbus.
The biggest change has to do with what is called the building’s podium — the base of the apartment building, which is made of steel and concrete. Until 2017, the podium level could be only one story. Now, there is no height restriction.
As a result, podium levels are rising two or three stories to accommodate commercial uses and garages below the apartments. Above that, the building is framed in wood. While the wood construction rises four or five levels, the building itself might climb to seven stories.
“With these podium buildings, you see the concrete podium (of) two or three stories, and then wood,” said Matt Canterbury, senior vice president of design and development at Columbus company Borror, which has built several apartment buildings and commercial buildings with wood.
“That’s the most cost-effective way. It’s the only way to actually pencil some of these projects out to make them affordable to do.”
Residential or office buildings up to 85 feet high can be built of wood, presuming they have full sprinkler systems, Ghosh said. Depending on the floor heights, that usually translates to a six- or seven-story building.
Beyond that, builders must switch to concrete, which is why so many apartment buildings stop at that height. Though building codes have long restricted use of wood over concerns such as fire risk and structural integrity, it’s less expensive in both material and labor costs than concrete and steel.
In addition to cost, wood has other advantages, said Canterbury and Seth Oakley, a principal with the Columbus architectural firm M+A Architects.
“Wood is renewable as opposed to concrete and steel,” Oakley said. “It’s also easier to achieve good sound ratings between floors with a wood structure. With a four-inch concrete floor, every footstep will translate.”
In the U.S. and beyond, wood has become far more common in residential high rises in recent years, driven by development of engineered wood beams called “cross-laminated timber,” designed for structural rigidity.
In March, builders finished a 280-foot, 18-story wood-framed building in Norway, thought to be the largest such building in the world. Also 18 floors, although much shorter, is the University of British Columbia’s Brock Commons in Vancouver, a wood-framed dormitory completed in 2016.
Several much taller wood-framed skyscrapers have been proposed, including the 80-story River Beech Tower in Chicago.
Wood framing is more common in residential buildings, which do not require the large spans of office buildings, but a 10-story wood-framed office building has been proposed in Cleveland. If built, it would be the nation’s largest wood-framed structure, according to the Plain Dealer.
While Ohio code doesn’t allow true high rises made of wood, experts say they expect wood to remain the standard in mid-rise buildings.
“I don’t see anything that would put an end to this,” Oakley said.