Five Reasons Four-Story Apartment Buildings Are Good

They’re naturally inexpensive. They’re often islands of physical accessibility. They’re supremely green without even trying—in part because they’re an essential ingredient for a truly walkable neighborhood. A lot of them are even sorta cute. 

They’re four-story apartment buildings, and they may be the most underrated building block of a healthy city or town, especially in the Pacific Northwest. 

Four-story apartment buildings hit a “sweet spot” of low costs and high benefits, according to Nathan Teske, executive director of Hillsboro-based affordable housing developer Bienestar. 

In the transect of housing types, a spectrum that runs from farmhouses to skyscrapers, this keystone of the Cascadia region’s potential future housing growth sits plop in the middle, nestled between the townhouse and the “5-over-1.” Here in the Northwest, four-story apartment buildings are almost always made of wood; under US building codes, they’re the tallest structures a team of workers can easily build without using more expensive, more complicated, and more energy-intensive concrete. 

If Oregon wants to start building more apartments, it should start thinking a lot about the number four.

Add all this to the shortage of construction labor and to overlapping state and federal prevailing wage rules that kick in with the fifth story, and you’ve got a good case that four is an even more magical number in our corner of the continent than elsewhere. 

“This is timber country, so folks [here] know how to build with it,” said Meaghan Bullard, managing principal at Portland-based Jones Architecture, which has designed market-rate and below-market housing in Astoria, Pacific City, Portland, and Seattle. 

As Oregon in particular looks for ways to accelerate housing production across the state without letting prices rise further, it may be coming to grips with the fact that removing the many regulatory barriers to new apartment buildings should be a bigger part of the solution than it has been so far. And if Oregon wants to start building more apartments, it should start thinking a lot about the number four. 

In my next article, I’ll explore how four-story apartment buildings have generally become illegal to build in Oregon, especially in the areas richest with jobs, infrastructure, and services where people actually want to live. For now, though, let’s take a short walk through the reasons why we should care about these four-story structures: four-story apartments are affordable to live in, inexpensive to build, and physically accessible; plus, they save energy costs and fit anywhere. 

1. Four-story buildings are inexpensive to live in

Unfortunately, the American Housing Survey doesn’t offer recent price data for the state of Oregon. However, it did recently conduct a survey for the half of the state’s population that falls within the Portland metro area, and here’s what it found:

Some of the savings compared to a detached home simply reflect the fact that most apartments are smaller than most oneplexes. But the benefit of having homes of various sizes on the market should be obvious: it lets people choose to save money by living smaller if they want to or if that’s what they can afford. Put another way: making apartments legal in more places lets people prioritize amenities or price, if that’s what they want, rather than just size. 

Then there’s the smaller price difference between smaller buildings and bigger ones—look at the rightmost bar on that chart. One reason it’s a little taller than the middle three is about location; the whole point of a high-rise is to fit many homes in a premium location. Some of it reflects a building’s age; because modern zoning leaves a so-called “missing middle” between oneplexes and skyscrapers, small apartment buildings tend to be older. But again, the chart above shows why midsize apartment buildings should be allowed to exist. If they aren’t, people get stuck with the more expensive extremes. 

But why four stories, not just three? In Oregon, four-story buildings are a perfect height for below-market affordable housing projects. Because federal tax credits that support these projects typically require at least 40 to 50 homes, and because the fifth story triggers state and federal prevailing wage requirements associated with public money, four stories is probably the single most common height of a below-market housing project in Oregon. 

If an Oregon neighborhood bans four-story apartment buildings, any smaller affordable housing project will be competing for cash with other non-apartment projects that are four stories tall, which will make it less likely to get funded. So bans on four-story apartment buildings are, functionally, major local barriers to state-funded affordable housing. A city may not be able to afford to build its own affordable housing, but any city can afford to let someone else build four-story apartment buildings. 

Of course, that’s no guarantee that homes will actually be built, and that’s O.K. Oregon’s law simply requires cities to do what they can. Anyway, there’s good reason to think that some of these homes will actually be built, because: 

2. Four-story buildings are inexpensive to build

Here is a recent survey of new construction costs by height in the 50 largest cities in the United States, via Brian Potter. Note that the vertical axis starts at $135 or so, not $0:

Source: Michael Eriksen and Anthony Orlando. “Returns to Scale in Residential Construction: The Marginal Impact of Building Height.” Real Estate Economics, 2021.

This is the other reason why four-story apartment buildings have lower rents than high-rises: because they can.  

Skyscrapers don’t exist—can’t exist, economically—until after the prices people are willing to pay for small spaces are already sky-high. Four-story buildings, by contrast, can start to sop up housing demand and bring prices under control much earlier in a rent surge.  

Why are low-rise apartments cheaper to build than skyscrapers per square foot? Because under US building codes, the eighth story generally requires steel girders rather than wood. Even adding a fifth story generally requires building the first floor out of concrete. Concrete construction requires different contractors with different equipment, rarer skills, and longer timelines, which add indirect costs. 

You might notice in the chart above that four-story buildings actually tend to be about 4 percent more expensive to build per square foot than three-story buildings. But that modest savings for three-story buildings is offset by another big factor: land costs, which might come to half of hard construction costs. Dividing that among four floors rather than three can save money overall. That said, one of the best things about a four-story apartment zone is that it also gives the option to build a three-story building if that’s better for some reason. 

3. Four-story buildings usually have elevators

This is a likely culprit for the small bump in construction costs with the fourth story: the $100,000 to $150,000 it costs to include an elevator. But here’s the thing: elevators rule.

A town that bans four-story apartment buildings is also banning accessibility.

You don’t have to read the Center for Building in North America’s big recent report or this New York Times op-ed to understand why (though I recommend reading both). Cascadia’s population, like the rest of the world’s, is aging fast. Already, many thousands of Cascadians who have mobility challenges—or just, y’know, grocery bags—live in cities and towns with very few residential elevators. Most towns do have a few buildings with elevators. But as a growing share of the population is over age 75, competition for homes in buildings with elevators is only going to get worse. 

More elevators are the antidote. But because of their high fixed cost, lifts very rarely go into buildings of two or three stories. A town that bans four-story apartment buildings is also banning accessibility. 

4. Four-story buildings save energy

One of the most important facts in environmental behavior is that there’s not a lot of difference in transportation-related energy use per person between a neighborhood that looks like this:

Image: Google Maps.

…and one that looks like this:

Image: Google Maps.

But both of these are dramatically more energy-efficient than a neighborhood that looks like this:

Image: Google Maps.

To put it another way, getting a Houston-like city to evolve into one more like Frankfurt would make a much bigger difference to the climate than getting a Frankfurt-like city to evolve into one more like Hong Kong.

Source: Jeffrey Kenworthy and Peter Newman, Cities and Automobile Dependence: An International Sourcebook. 1989.

Here’s another look at that phenomenon, but this time just within a few metro areas in the United States:

Source: John Holtzclaw, Robert Clear, Hank Dittmar, David B. Goldstein, and Peter Haas. “Location Efficiency: Neighborhood and Socio-Economic Characteristics Determine Auto Ownership and Use.” Transportation Planning and Technology, 2010.

When it comes to giving people alternatives to the energy-guzzling automobile, the biggest gains fall in that leftmost part of those charts, as households per acre go from 1 to 40. You can’t find 40 households per gross acre in a neighborhood of detached homes, townhomes, or two-story walkups. But you can easily find it in a neighborhood with a mix of detached homes, townhomes, and two-story and four-story apartment buildings—in other words, in the sort of neighborhood that might take root in an area zoned for apartment buildings up to four stories. 

Not everyone wants to live in that sort of neighborhood, and not everyone should be required to. But every time someone does choose to, it helps everyone else. It cuts air pollution, keeps cars off the road, and preserves electric capacity. So, again, we should make it an option for anyone who does want to live in that sort of neighborhood, by allowing four-story apartment buildings on a decent amount of land in every city and town. 

5. Four-story buildings can fit anywhere

Here are some four-story buildings in Utrecht:

Photo by Ted McGrath (Creative Commons)

…and in Portland:

Photo by Mark McClure (Creative Commons)

…and Eugene:

Image: Google Street View.

…and Hillsboro:

Image: Google Street View.

…and Ashland:

Image: Google Street View.

…and Canby:

Image: Google Street View.

…and McMinnville:

Image: Google Street View.

Four-story buildings don’t loom. They’re a little shorter than the width of a typical US street, including sidewalks. Especially when they’re allowed to exist without excessive parking lots and garages, these buildings can add to a block without utterly transforming it. 

Four- to five-story buildings are “a really strong typology for walkable, livable cities,” said Bullard, of Jones Architecture. “It’s a very human scale.” 

Should big cities allow some buildings to be taller than four stories? Yes, of course. But in most cities and towns, there’s no need. Four stories are good. And four stories are enough.