Washington, D.C. is running out of space. With cranes and new residential developments regularly blocking one's view, it shouldn't be a surprise. Already, the District is set on breaking population records by 2040, increasing from 659,000 to 900,000.

With the Height Act in place, there's only so much space that can be filled by housing. Additionally, 61 percent of respondents to a Washington Post poll said that they preferred the restrictions in place, so there's little pushback on getting rid of it. But in the end there's only so much area to fill.

So, what is the city to do to keep up with the growing populations?

One possible solution is to utilize alleys. Currently, regulations only allow dwellings to be built in alley networks or alleys that are 30 feet wide. When it comes to how high these homes can be, that all depends on the width of the alley it fronts and whether or not the developer was given variance approval from the Board of Zoning Adjustments.

Already, Washington, D.C. is well under way towards redeveloping alleys for housing, retail, restaurants, and parks.

There are currently plans for a two-building, 121-unit mixed-use development in Shaw, named after the alley it's located in, Blagden Alley. D.C.'s Board of Zoning Adjustment approved Blagden Alley in March of 2015, despite there being no plans for providing any parking spaces. To approve this, developers SB-Urban and Rooney Properties had to pay up $70,000 for a 27-dock Capital Bikeshare station with memberships for each resident. The residents intended to fill up the short-term micro-units are “slightly higher-income, more upscale tenant[s].” (It’s worth noting that the D.C. Court of Appeals rejected this relief in January 2017.)

In Mt. Vernon Triangle, Prather's Alley was once a hotspot for speakeasies and crime. Now, it is a popular pedestrian route. In 2014, The Wilkes Company hoped to further redevelop the site with ground-floor retail, but ran through too much red tape.

In July 2015, D.C. Mayor Muriel Bowser and District Department of Transportation Director Leif Dormsjo also kicked off, "AlleyPalooza," a $16 million campaign set to repair or renovate a 64 alleys by September of that year.

Redeveloping alleys as a method to re-activate cities isn't a new idea. In Denver, there were plans to pave 150 unimproved alleys by 2016. In the fall of 2013, one alley under the Evans Avenue Bridge that Model D described as "an absolutely forgotten urban place" was redeveloped with pop-up beer gardens and a coffeehouse.

The purpose of redeveloping alleys isn't necessarily to solve a housing problem, though. The beautification creates new public spaces and new identities for neighborhoods.

Not only that, but these small spaces can even be seen as small steps towards progress. In Philadelphia, a neighborhood organization, known as Center City Residents Association (CCRA), partnered with Philly-based Shift_Design to craft a proposal with different ways in which grungy alleys could be reactivated. Birdhouses, LED-lighting, foliage—all these things and more were described by Center City based blogger William West as a step in the right direction.

In the fall 2015 CCRA newsletter, West wrote:

It's a shame that some of the city's prettiest streets are backed up by these automotive shantytowns. We might as well put up a sign: Abandon All Standards, Ye Who Enter Here. That's how it is, but I don't think it's necessary. All we really need to do, I think, is pay a little attention.

These not-quite-streets are significant, and they make a bigger impact than one might first think. Redeveloping them with retail or housing not only fosters more activity in an area. They cause those who are always near to feel safer and prouder of their home.

Model D further rallied for utilizing alleys rather than disregarding them, writing:

While U.S. cities have largely eschewed alley uses that don't involve garbage or garages, pre-automobile cities all over the world have historic alleys that were meant for people, complete with housing, stores, restaurants, bars and parks.

How do Washington, D.C.'s alleys influence the city's identity? According to Washington City Paper, these spaces—from the pastoral blocks in the Palisades to the grease traps in Downtown—are intimate, relaxed spaces that contrast the uptight metropolis we live in.

Despite the resurgence of alley dwellings in the city, living in an alley in Washington, D.C. never used to be appealing. These abodes were often in unlivable conditions and housed those with lower incomes. They were essentially overpopulated slums, or as James Borchert wrote in his 1980 publication Alley Life in Washington, "mini-ghettoes."

In the the book, Neglected Neighbors, former Executive Officer of the Associated Charities of Washington, D.C. Charles Weller wrote that the alley dwellings during this time primarily housed the city's working-class black population. Borchert wrote that alley residents were also often migrants from the countryside who "suffer[ed] from the disorientations of urban life."

Because they were more often than not hidden from sight, alley dwellings were also often areas of crime and disease. Alleys of this kind aren't unique to cities, but Washington, D.C. was unique in how widely dispersed black residents were. These structures were made from the cheapest of materials: lumbar, covered with felt and tar. Some of these apartments measured 12 feet by 14 feet.

Housing pressures and racism caused these dwellings to flourish. In Foggy Bottom in particular, the number of households jumped from 40 in 1822 to 175 in 1860, according to Suzanne Berry Sherwood in her 1978 publication, Foggy Bottom, 1800-1975: A Study in the Uses of an Urban Neighborhood.

As a whole, Borchert wrote that the D.C. population skyrocketed from just over 60,000 in 1860 to nearly 110,000 just 10 years later. The increased pressures on land as well as the lack of a public transportation system further influenced the growth of alley dwellings throughout the city. Eventually, by 1860, "land-efficient tenements" replaced alley dwellings in major cities, according to Borchert.

Alley dwellings concentrated most around the White House, Capitol, Navy Yard, south of the National Mall, and between 3rd and 15th streets NW.

Pierre Charles L'Enfant never planned on there being alley communities in the District. Even so, his design influenced their development due to the large, open plots of land in the city, which gave enough space for building much smaller dwellings, according to Former Historic Preservation Specialist of the Historic Preservation Board Eldra D. Walker in her project for the Historic Preservation Program at the University of Pennsylvania.

With this new housing came Washington, D.C.'s first public housing agency in 1934, the Alley Dwelling Authority. The organization's purpose was to evaluate whether or not certain houses and streets were in conditions that were actually livable. With this organization and with later influence from Eleanore Roosevelt, many of these alley dwellings and their often unsanitary conditions were eliminated. Entire alleys were torn down, and residents were displaced. This occurred despite Roosevelt's goal for residents to remain in their homes once improvements were made.

When the Board for Condemnation of Insanitary Buildings was created in 1906, this led to the razing of 375 alley dwellings between 1906 and 1911. During that time, 315 dwellings were repaired, according to Borchert. By 1927, nearly 40 percent of the abodes were no longer in use. The automobile industry also influenced the removal of alley dwellings as garages grew year by year, taking over the sites where these dwellings once were.

The Alley Dwelling Authority finally officially banned the use of alley dwellings in 1955.

In the end, Washington, D.C. is running out of space, and alley dwellings may be a method to create more housing. In April 2015, Senior Editor of Washingtonian Maria Kashino wrote that D.C. has less than a 30-year supply of land that can be developed. This takes into account the number of households and jobs expected to rise by 2040, while also calculating the amount of buildable space needed to accommodate them.

While crunching these numbers, Kashino described the scenario as "bearish" and "bullish," but focused on how there is a need for the District to change its approach on whether or not to change the height limit—at least in areas that don't interfere with the historical character of the city.

Cramming residences in smaller spaces may not be the way to go for Washington, D.C., but it may be more popular than building a taller Washington, D.C.

In the end, something's gotta give.

• Zoning Changes in Depth: Alley Dwellings [UrbanTurf]

• Unless Washington Makes It Easier to Build, We’re All In Trouble [Washingtonian]

• Examining the Dark Side of Washington, D.C.'s Height Act [Curbed DC]

• Rep. Darrell Issa links Redskins with Height Act [The Washington Post]

• Urban alleys become pathways to revitalization [Model D]

• The Mysterious Charms of D.C.'s Alleys [Washington City Paper]

• Philly's Grungiest Alleys May Get a Much-Needed Makeover [Curbed Philly]

• Alley Dwellings in Washington, D.C. [Bryn Mawr College]