These buildings are in almost every U.S. city. They range from three to seven stories tall and can stretch for blocks. They’re usually full of rental apartments, but they can also house college dorms, condominiums, hotels, or assisted-living facilities. Close to city centers, they tend toward a blocky, often colorful modernism; out in the suburbs, their architecture is more likely to feature peaked roofs and historical motifs. Their outer walls are covered with fiber cement, metal, stucco, or bricks.
The number of floors and the presence of a podium varies; the key unifying element, it turns out, is under the skin. They’re almost always made of softwood two-by-fours, or “stick,” in construction parlance, that have been nailed together in frames like those in suburban tract houses.
In the U.S., stick framing appears to have become the default construction method for apartment complexes as well. The big reason is that it costs much less—I heard estimates from 20 percent to 40 percent less—than building with concrete, steel, or masonry. Those industries have sponsored several studies disputing the gap, but most builders clearly think it exists.