As land prices soar, Seoul places its next public housing project on highway

A computer-generated illustration of a public housing complex to be built atop the Bukbu Expressway in Jungnang-gu, northeastern Seoul. / Courtesy of Seoul Housing & Communities Corp.

'Building on elevated decks is more economical than ground-level construction'

By Lee Suh-yoon

Seoul is running out of space for new public housing projects.

For years, commercial real estate development has pushed up land prices in the city. Greater costs follow public projects that require buying and building on private land. In response, Seoul Housing & Communities Corp. (SH), Seoul's public housing builder, is eyeing what might be considered relatively "vacant" public land, such as bus garages and water treatment centers.

On Monday, SH announced a pilot project for one such underused space ― the air above a congested highway.

The plan looks too simple to actually work. A flat-topped rectangular tunnel is placed over a 500-meter section of the Bukbu Expressway in northeastern Seoul. A multi-floor housing complex for at least 1,000 households with flanking gardens is then placed on top of this hollow structure, straddling over speeding cars.

The public builder claims the engineering feat is both doable and cost-effective.

"Under the circumstances, it's an economical solution. Land prices have soared while engineering costs have fallen comparatively," Kim Sei-yong, head of SH, explained at a press conference on Monday where he unveiled the preliminary blueprint for the project.

The 500-meter-long deck over Bukbu Expressway could create up to 23,500 square meters of new space around 10 meters above the ground. According to SH, the expected cost of building such a deck capable of supporting high-rise structures is only 70 percent of the cost of buying the same area of land near the chosen site.

Another 51,000 square meters of public and private land on either side of the motorway will be connected to the raised platform and incorporated into the housing complex. The expected total budget ― including the cost of buying privately owned land included in the plan as well as engineering and construction costs ― is 421.3 billion won ($347 million).

Land is a contested resource in Seoul. Ten million residents ― one-fifth of the nation's population ― vie for space within the outer rims of the 600-square-kilometer metropolis. An increasing number are priced out each year to the surrounding Gyeonggi Province, and spends hours on the road or underground commuting to work in Seoul.

A possible image of what the public housing complex will look like from the side next to the expressway / Courtesy of Seoul Housing & Communities Corp.

Old neighborhoods are erased every day to make way for new apartment complexes and high-rise condos. But with investors gobbling up housing units and traditional four-to-five person families splitting into many more one- or two-person households, there is never enough housing to go around.

The term "affordable housing" is an oxymoron for most Seoul citizens now. A host of macro policies introduced by the current Moon Jae-in administration has done little to normalize housing prices.

One way low- and middle-income residents maintained a foothold in Seoul despite all this was public housing. There are over 300,000 public housing units in Seoul and Seoul Mayor Park Won-soon plans to increase this number to 400,000 ― around 10 percent of the total housing market ― by 2022.

The idea of building the next public housing complex over a highway didn't come from city officials or engineers. The idea was drawn from abroad, most notably Germany's Schlangenbader Strasse. Built in the 1970s by architects Georg Heinrichs, Gerhard Krebs and Klaus Krebs, the megastructure is dubbed the "snake" due to its winding form over a 600-meter section of a highway. Though there were some structural problems at the time of construction, the current residents of the 1,064 apartment units inside show high levels of satisfaction with the motorway housing complex, according to German media outlets.

Like the Schlangenbader Strasse, the Bukbu Expressway housing complex will be focused on creating an attractive living infrastructure rather than fitting as many housing units as possible in the given space. Communal spaces like libraries and swimming pools as well as co-working spaces for startups will be incorporated into the buildings. In line with the decreasing number of traditional four- to five-member households in the population, the apartments inside will be designed for one- or two-person households ― young people or young married couples without money to break into the commercial real estate market.

SH says it can keep all car lanes on Bukbu Expressway open during construction to minimize drivers' inconvenience. Nearby residents will likely suffer from some noise or dust pollution during the construction period, but once completed the neighborhood will benefit from the enclosure of traffic noise and pollution, it said.

SH also plans to line the tunnel with sound-absorbing boards. Six pedestrian skyways will connect the elevated deck to the nearby railway station and residential areas, previously cut off from each other by the highway.

Construction for the complex will start in the latter half of 2021, after the final design is picked through an international contest this year.