These new high-rises are made of wood
Like many Americans, I grew up in a house made of wood. A wood-frame house is cost-effective, quick to build, and adaptable for different designs. Most have a concrete foundation. The floors are made of wooden beams, called joists, and the frame is made from vertical two-by-four or two-by-six pieces of lumber. This is the standard for one- and two-story homes in the suburbs and small towns of North America.
Wood used to be popular in big cities. Buildings, and even sidewalks, in some of America’s biggest cities were made of wood. But then, several cities were hit with major fires—Philadelphia in 1850, Chicago in 1871, Boston in 1872, and San Francisco in 1906. Fire swept quickly through wood buildings, destroying major parts of those cities. That put an end to wood construction in dense areas.
Today, most buildings in cities, and most commercial buildings, are constructed of brick, concrete, or steel. Many large cities prohibit wood construction over about three stories. But recently, wood has been making a comeback.
When I say “wood,” I don’t mean the two-by-fours that frame single-family homes, like the ones in my neighborhood growing up. I’m talking about something called “mass timber.” Mass timber refers to wooden panels and beams that can support tall buildings.
Think back to the last time you saw a tall building under construction. You probably saw tall concrete columns, or even steel beams. You may have seen concrete slabs form the floors on each story. In a timber building, all that is made with heavy, solid wood panels and beams.
These are made by gluing layers of lumber together, either in the same direction or perpendicular to each other. Panels are several inches thick and can work just as well as a thick concrete slab.
This new type of material allows architects to build much taller buildings with wood—think eight, ten, even twenty stories in the air.
Benefits of mass timber
There are several benefits to timber construction. Ironically, the first is environmental. Yes, to build a timber building, you have to cut down trees. But trees are a renewable resource. In a well-managed forest, trees can be replanted, and they grow back to full size in about a decade. And producing timber requires much less pollution compared to producing concrete or steel. The timber also acts as a carbon sink. That means it captures and stores carbon, reducing greenhouse gasses in the atmosphere.
That’s one benefit. Another is efficiency. Many of the components that go into a mass timber building are produced off-site in a factory. They’re then transported and assembled at the construction site. That’s more efficient than pouring concrete on-site. It’s also easier to control quality when more parts are made in a central location.
There are fewer days lost to bad weather and fewer workers required on-site. Timber is lighter than steel or concrete, and cranes can more easily lift the pieces into place.
Those are the practical benefits. But there are softer ones, too. People like being in buildings and places that resemble nature. Exposed wood interiors create a warm, natural ambiance. A space feels cozy and alive when there is exposed wood. Studies have shown that being surrounded by wood can lower stress, reduce blood pressure, and improve comfort for occupants.
Challenges to wood construction
Still, you might be wondering—wood? Really? If that’s what you’re thinking, you’re not alone.
There are drawbacks. Wood is organic, so it’s susceptible to decay, moisture, and pests. The timber structure has to be protected from water. That means treating the wood with water-resistant seals or coatings. Many timber building exteriors are wrapped in membranes or covered in sidings, like brick, to protect the wood from the elements.
What about fire—the original reason wood buildings were limited in big cities? The new timber structures are more fire-resistant than before. In a fire, the structural elements char on the outside, which creates an insulating layer that prevents the rapid spread of a fire. Tests show that timber framing can stay structurally sound for several hours during a fire.
Cities are updating their fire codes to allow for taller timber buildings. They require sprinklers, fireproof coatings, and limits on how much timber can be exposed to the interior.
Examples of tall timber buildings
So where has this been done? Mass timber construction is more popular in Europe than it is in North America. In Sweden, it’s easy to produce mass timber buildings because 70 percent of the country’s land area is covered in forest. And they’re not running out of trees: Since 1903, the country has required reforestation, so there’s more tree cover now than there was a century ago.
Stockholm Wood City is a plan to build 250,000 square meters of timber-built commercial and residential space across 25 city blocks in Sweden’s capital. That will include 2,000 homes, space for 7,000 office workers, plus shops and restaurants—essentially, a whole neighborhood made of wood. Groundbreaking is expected this year, 2025, with a target completion date in 2027.
There are not many tall buildings in Brumunddal, Norway, but there is one. Mjøstårnet is an 18-story tower completed in 2019. At the time, it was the tallest wood-construction building in the world. It proved that the new engineered timber is strong enough to support a tall tower. It’s home to the aptly-named “Wood Hotel.”
The city of Skellefteå, Sweden, has a 20-story timber building. It’s a complex with theaters, an art gallery, and a library. Confusingly, it also has a hotel called the “Wood Hotel,” but it’s not the same as the one in Norway. The town also has schools, bridges, and even parking garages made of wood.
Austria is home to a 24-story wood tower that opened in 2017.
North America has been slower to adopt modern timber construction, but Milwaukee, Wisconsin, boasts the world’s largest timber building. That is the Wood Hotel—no, I’m just kidding. It’s called the Ascent Tower, a 25-story apartment building. An 18-story student residence hall was built in Vancouver, Canada.
In Australia, a 40-story hybrid skyscraper is expected to be completed this year. It’s a hybrid because the exterior will be steel and glass, but the internal structures—like the floors—will be timber. That is expected to open in 2025 and will be home to the software company Atlassian.
Jeff’s take
I must admit—I love old industrial interiors. I love buildings that have exposed timber beams in the ceilings. Chicago has lots of old brick and timber buildings that have been turned into apartments, offices, and stores. They’re so interesting to look at, to be in. Those studies that say people feel good, feel less stress when they’re surrounded by natural-looking materials—I believe them. I’d love to live in building with exposed timber on the inside.
But a whole building made of wood? I wasn’t sure what to think. At first, I pictured a log cabin on the inside. But it really doesn’t look like that. Some of the designs do have exposed wood. But a lot of the buildings have huge windows. And in many buildings, the wood is covered up—you don’t even see it on the outside or the inside, so you might not even know you’re in a wood building.
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