Long, thin pieces of wood hold up many of the University of Minnesota-area’s newest apartments.

Slender wood pillars and a sheath of plywood, or a similar material, wrap some of the rooms inside housing complexes like the Marshall, the Knoll and the Elysian.

Other new complexes are made of concrete or steel.

The decision about which material to use when constructing housing for hundreds of University students often comes down to cost and resource availability.

In the recent wave of near-campus construction, wood has emerged as the material of choice for many developers, who say the product is more cost-effective, easier to use and just as structurally sound as any other material.

The now-formulaic “stick-built” construction style — with retail space on the bottom floors with 100 or 200 rooms stacked on top — isn’t exclusive to the area, but is part of a growing trend across the Twin Cities.

How to do stick-built

Building an apartment from wood means relying heavily on state and international building codes.

Minnesota laws, along with the International Building Code, dictate that wood-frame apartments cannot be taller than six floors, with some exceptions.

That restriction is based on the height of firefighters’ ladders, said associate architecture professor Blaine Brownell, in the case of an emergency where a firefighter has to reach a building’s top floor.

Contractors can also use wood treated to be less susceptible to flames, mold and other types of wear and tear. In some cases, they’re mandated to do so.

The height limit on stick-built apartments can be slightly extended with the addition of a sprinkler system, according to the IBC.

But Brownell said that adding a sprinkler system rarely yields a return in investment, since it’s often an expensive addition that doesn’t create much more living space in a building.

On the other hand, concrete or steel buildings can reach well above six stories, though their height limits vary by geographic area.

All but one of developer Kelly Doran’s six luxury student housing projects are made of wood. The Bridges, which opened in fall, is 11 stories high, said Scott Casanova, Doran Companies’ vice president of major projects.

Around the University, many complexes sit on a concrete base often used for retail space, like TargetExpress and Gina + Will under the Marshall and the Venue, respectively.

The timeline for building wood-frame projects generally falls around a year, Brownell said.

With the pace of construction that the stick-built method allows, Brownell said concern is natural.

“Speed can sometimes mean that something is put together less thoughtfully or carefully,” he said, “but at the same time there are demonstrated practices where construction can occur incredibly quickly and be tightly coordinated.”

Wide benefits, tall drawbacks

When balancing the pros and cons of construction materials, industry experts say wood typically emerges as the most cost-effective answer — which is a big part of why developers and architects tend to select it for housing both around and beyond the University area.

While it’s logical to assume that wood construction is also the most fragile, Brownell said, the reality is that stick-built apartments are built to last.

“Just because a structure is made out of wood, psychologically it might seem to be cheaper or less stable or sturdy,” he said, “but then you’d really just have to just look at the way that something was designed and built versus the material that was used.”

Brownell said the cost of the manpower to construct a building, rather than the price of the resource itself, can drive the decision about what kind of construction material to use.

Building with steel or concrete requires hiring crane operators and a larger number of workers. Wood calls for fewer resources, making it a more attractive option, Brownell said.

Industry experts say concrete and steel buildings are preferable if the structure’s lifetime needs to exceed 100 years, but they say wood-framed apartments will last long enough for their purposes.

Daniel Oberpriller’s development company, CPM Companies, owns at least five completed or under construction housing complexes in the University area.

“Obviously a concrete building will last longer than a wood building over the course of hundreds of years,” he said, “but how many hundreds of years do you need these buildings to last?”

WaHu, a project currently under construction on the corner of Washington Avenue Southeast and Huron Boulevard Southeast, is CPM’s only steel complex.

Oberpriller said it’s a “gateway building” that sits at an entrance to the campus area, so it was designed to be large and visible. That kind of size, he said, requires a steel skeleton.

Still, Oberpriller said, wood-framed construction isn’t an inferior alternative.

Concrete and steel are preferable for offices and hotels, Brownell said, because those buildings tend to be taller.

And because the walls in steel or concrete office or apartment buildings typically aren’t all weight-bearing, they can be remodeled into different types of buildings — which isn’t an option for stick-built complexes.

Because it’s more expensive to construct with concrete or steel, once the six-floor maximum has been reached, it’s better to build even taller than seven or eight stories, said Dean Dovolis, owner and founder of DJR Architecture.

Because the materials and labor cost more money, he said, a developer can get his or her money’s worth out of a project by pushing the project upward.

Ward 3 City Council member Jacob Frey said though he understands that the wood-framed structures meet a local housing need, he prefers tall, thin concrete structures.

“The benefit of building tall and elegant is that you free up activity to take place on the ground level,” he said. “If you did a six-story building you would have to build this wide behemoth structure that blocks out the sun.”