In this Southwest Voices housing affordability series, I’ve discussed some of the local policy issues that exacerbate our housing shortage and limit our ability to build new housing in quick, cost-efficient ways. I’ve also dug into the Minneapolis 2040 Comprehensive Plan, which set in motion a great deal of local policy change that sought to increase housing development — that is, until the plan was recently put on hold due to an environmental lawsuit, leaving Minneapolis to comply with its previous comprehensive plan and undo changes to allow increased housing. This plan contained both successes and shortfalls in achieving that goal.

Minneapolis is not the only city that has changed policies to get more housing built, and to do so at cheaper costs. In this article, we’ll travel to three cities that have their own housing reform success stories to share. We’ll look at skinny townhomes in Houston, fourplexes and “cottage clusters” in Portland, and “single-staircase” apartments in Seattle.

Houston, Texas: home of the “tall skinny houses”

'Skinny homes' in Houston, Texas. These townhomes, built on smaller, narrower lots, replaced single family homes in Houston. Photo by Sandra Wegmann.

Houston has a reputation as an American city that doesn’t have “zoning” in the vein of most American cities — it’s quite flexible in allowing buildings of various sizes and types across the city. But until 1999, Houston did have a similar minimum lot size requirement to Minneapolis. Houses had to be built on at least a 5,000 square foot plot of land.

In 1999, the city significantly reduced these restrictions, allowing for townhomes to be built on lots with just 3,000 square feet. In comparison, 5,000 square feet is the minimum in Minneapolis. As one study of this change documented, Houston’s zoning reform facilitated a local trend towards homes built on skinnier, smaller city lots. When developers no longer needed special approval to build homes on less land, homes that sat on lots smaller than 5,000 square feet were built by the thousands.

“Developers were already building this product via variances [i.e., special approval from city planners], which tells you that they really wanted to build this product and people wanted to buy it,” said Jake Wegmann, a city and regional planning professor at the University of Texas at Austin.

The cost of land typically represents a large share of buying a home. Allowing people to build and purchase homes that use less land can contribute to significant reductions in the cost of housing. Research supports this. In Wegmann’s recent research, he found that in places where new townhomes had replaced single-family homes, the townhomes were valued at an average of $340,00. Single family homes built over the same timeframe were valued at an average of $545,000.

Two beneficial things are going on here. Though it’s no surprise that smaller homes cost less, it’s striking that those smaller, more affordable homes were in violation of local planning rules — even though many people were willing to buy them. Then there are the secondary effects on expanding housing supply, and ensuring sufficient housing will be available across the city.

Wegmann notes that on their own, these reductions in housing costs won’t do enough to reach the lowest-income people. But still, he says, such changes are important.

“I would argue that it’s a big improvement if the costs come down, even if you’re not reaching the most low-income people,” Wegmann said. “It’s less of a lift to subsidize housing under those circumstances, and more people have more choice. To me, it’s still progress, and I don’t see any contradiction.”

Portland, Oregon: neighborhood-scale “stepped density”

A "cottage cluster" in Portland, by Studio Cropp Architecture. This project includes four homes built around a shared courtyard — all on a single city lot. Photo courtesy of Studio Cropp Architecture.

In 2020, Portland, Oregon passed the “Residential Infill Project,” a change reminiscent of the Minneapolis 2040 Plan’s city-wide triplex legalization. In just about all of Portland’s neighborhoods, it is now legal to build up to four units on the same lot.

But Portland’s broad legalization of multi-unit housing came with different details than those in Minneapolis. As I discussed in the previous segment of this series, the Minneapolis 2040 Plan allowed duplexes and triplexes in name, but maintained other rules that make those buildings mostly impractical to build. In Minneapolis , a triplex on a typical neighborhood lot would have to squeeze its units into a single family-sized building, often making triplexes infeasible to build. For fun: try to design a triplex within an existing house without adding any extra floor space. In essence, that was a provision written into the 2040 Plan.

Portland, on the other hand, allows the building size to “step up” as a building gets more housing units.. As Portland Senior City Planner Morgan Tracy explained, if new projects have more housing units, they also get a bit more space.

“The Planning Commission gave us direction, ‘we want to provide a disincentive to building just a single house and we want to really encourage these other housing types.’ So we wanted to ratchet up the amount of square footage [developers] get [for building more units], while at the same time, each of those units is getting progressively smaller, so thus more affordable,” Tracy said.

In just the first year after implementing these changes, Portland saw 271 newly-enabled housing units built in small-scale multifamily housing, such as fourplexes and “cottage clusters,” which are groups of small, detached homes built around a shared courtyard. This represented more housing than single-family homes built in Portland in the same timeframe, and more housing than all duplexes and triplexes built in Minneapolis in the two and a half years after the 2040 Plan.

Jill Cropp, an architect in Portland who has designed many neighborhood-scale housing developments, discussed how these rules impact affordability by comparing prices in the pricier neighborhoods of central Portland.

“A brand new 2,500 square foot house, which is the biggest brand-new one you can get, that will be probably a million dollars, maybe $900,000 [in those neighborhoods]. Ones that are 3,000 square feet or more, can be $1.2 million. But if you built a cottage cluster, they probably would go for more like $500,000, $550,000 on an 1,100 square foot cluster,” Cropp said.

And as you go further outside of the most central neighborhood in Portland, you can find new small-scale, multi-family homes for even less. Tracy told me about brand new fourplexes, where ons unit can sell for as little as $400,000 — certainly not cheap, but a large relative cost difference for Portlanders.

Just as in Houston, these aren’t changes that will singlehandedly solve Portland’s housing cost woes. But they make a meaningful difference.

Seattle: the single-staircase mid-rise

A new four-story, 10-unit apartment with only one single staircase in Seattle, by CAST Architecture. With just one staircase, this new building could be built on a single lot while preserving the adjacent buildings. Photo courtesy of CAST Architecture.

North of Portland, Seattle is seeing the results of a different building innovation than four-plexes and cottage clusters. Like Houston’s tall skinny houses, Seattle has seen a steady stream of slim apartments that can easily slot into existing neighborhoods.

Michael Eliason, a Seattle-based architect and advocate, has spent the last few years advocating for changes to building codes that would make housing easier to build, while also making that housing more livable and family-friendly. Somehow, Eliason has found a housing policy issue even more wonky and technical than triplex zoning rules in the 2040 Plan. Eliason wants to let mid-sized apartment buildings get built with just one staircase, instead of the two staircases typically required in taller apartment buildings.

Eliason argues that most American cities, including Minneapolis, have made a huge mistake in their building codes, which require all apartment buildings taller than three stories to have two staircases. Requiring two staircases forces apartment buildings to include a long, narrow hallway down the middle of the building — a “double-loaded corridor” — and because so much space is dedicated to the hallway, floor space is inefficiently utilized. On top of that, requiring two stairways limits housing development towards very large buildings that can’t just be built on an individual urban lot.

“The way we do development in the US, our building code induces these larger buildings,” Eliason said. “All the new buildings in downtown cores are massive, thick, and require parcel assemblage [the expensive and time-consuming process of attaining multiple land parcels next to each other to build a bigger building].”

Seattle is a bit different. In response to a 1970s housing crisis, the city’s building code allowed apartments as tall as six stories to have just one staircase. As a result, the city has seen many space-efficient apartment buildings that add much-needed housing in Seattle, and have just one staircase. Eliason believes that these designs are safe, too, if we’re attentive to other fire safety details — he points to many European and Eastern Asian countries that allow tall apartments to have just one staircase, while maintaining similar or better building fire safety than the United States.

It’s a bit harder to precisely quantify the affordability of these apartments. Unlike the examples highlighted in Houston and Portland, these apartments aren’t necessarily rented for significantly less than other apartments. Allowing single-staircase apartment buildings to bloom ,which, in Minnesota, would require a statewide building code reform, can be a powerful tool to help address our detrimental housing shortage, allowing more homes to be built in places that they otherwise wouldn’t fit.

And that’s before you weight the other benefits that Eliason espouses about single-staircase buildings: In addition to being more cost-efficient to build, he says, these buildings are better-equipped to meet energy efficiency standards, have apartment units with more windows and airflow, and have the space to build more apartment units with higher bedroom counts that support families.

Learning from other cities

These cities each highlight how changes to highly technical housing regulations can make big differences to housing affordability. Smart policies to allow more housing that is built more efficiently will help our neighbors find a place to live.

Two caveats are important. For one, regulatory changes are only one piece of the puzzle for addressing our housing needs. They can’t fix everything alone. Lower-income residents will always need subsidies of some kind, and lower-cost housing doesn’t guarantee housing stability.

And second, housing policy in each of these cities was born of a particular political and policymaking context. Houston has a very unique set of urban planning institutions and local political structures. Portland’s “stepped” density, in which they allow buildings with more housing units to have more square footage, was in part enabled by a backlash to already-humongous, single-family “McMansions” being built in the city. Seattle’s building code allowed six-story buildings to have a single staircase during a 1970s housing crisis, leaving it unique among nearly all of its North American peer cities. Minneapolis cannot precisely replicate these unique contexts.

Nevertheless, these cities can provide a signpost for the kinds of housing policy success that Minneapolis should keep aspiring toward.

The Southwest Voices Housing Affordability series is sponsored by Housing First Minnesota.