Fernando Abellanas thinks he just might have come up with a solution to the lack of space in many big cities. The Spanish designer earlier this year created a workspace that literally hangs off a highway in Valencia, Spain.
With a suspended floor made of plywood boards and metal tubes, this makeshift studio actually uses the concrete overpass as its walls and roof. The structure also takes advantage of beams under the bridge: It uses them as a framework along which it can side on a set of wheels.
Measuring 7 by 7 feet (2.2 by 2.2 meters), this is a no-frills space furnished only with a chair, artworks and photos and a desk. It took Abellanas just a week to build.
"I am interested in rethinking what is established, in analyzing these types of spaces and investigating (their) alternative uses," Abellanas tells CNN.
Fernando Abellanas is pictured at his studio space. Credit: Fernando Abellanas
Abellanas' work is more abstract in its concept than it is a "concrete solution" to housing issues -- rather an "invitation" for people to reflect on the use of spaces, he says.
He's not alone. From Paris to Thailand, creative minds are using "parasite architecture" in increasingly creative and practical ways to help us reconsider urban space.
Simply put, parasitic architecture is defined as a building that is attached to an existing larger structure. It developed in response to the need to solve common city problems such as high rents and a lack of space, and even to provide respite from suffocating heat as congestion builds in urban areas.
James Furzer, a UK-based architect, began working on "parasitic pods" in 2015, with the hope of creating a feasible, affordable housing solution for the disadvantaged.
Inside the a homeless shetler created by James Furzer. Credit: James Furzer
Furzer tells CNN that his creations were a response to the influx of "hostile architecture" in cities -- a controversial type of design intended to prohibit people from using public spaces in certain unsanctioned ways. Examples of this include benches that are sloped or fitted with spikes to discourage homeless people from resting on them.
"The shelters (pods) derived from my ambition to create an architecture that is available and accessible to all walks of life, not only those that can afford it," he adds.
About 6.6 by 6.6 feet (2 by 2 meters) in size, Furzer's pods provide "the fundamentals of shelter" -- warmth, protection from the elements, and comfort.
The shelters derived from my ambition to create an architecture that is available and accessible to all walks of life.
James Furzer, architect
They cost between $5,430 and $6,785 each to build, and are made from scrap materials. They are designed to be fixed to structurally sound buildings -- ideally, government-owned sites such as warehouses or car parks.
Furzer is currently in talks with a private investor, and together they are looking to develop a scheme that ensures these pods can be rolled out and constructed at minimal cost.
"I do not envisage architecture such as this to be readily available for a few years yet, but it is developing in the background to become a feasible product," he says.
Across the globe in Bangkok -- a city of at least 8.2 million people, and with some of the world's worst congestion
-- the All(Zone) architectural firm has an illuminating take on the trend.
Their creation, The Lighthouse, debuted at the 2015 Chicago Architecture Biennial. Currently a prototype, it is made from a metal grid, which is surrounded by a nylon net that provides mosquito prevention and privacy.
Covering 124 square feet (11.5 square meters) and costing $1,000 to build, it was envisioned as a nomadic living space that can be quickly installed and taken down.
The Lighthouse, being a lightweight shelter from the heat, is also an "attempt to create a new type of domestic space in a tropical metropolis", All(Zone) said in a statement made at the the Biennial.
"Light" in Lighthouse's name refers to its weight and transparency, says the architect. Credit: All(Zone)
"(There is) no need to (suffer) ... the weather in a tropical climate if you are under a shade," Rachaporn Choochuey, architect and co-founder of All(Zone), tells CNN.
"We try to communicate that there is no need to build heavily in such a climate."
The nylon walls, however, are translucent, meaning that when a light is on inside silhouettes are clearly visible to outsiders.
"The locals were really interested in the Lighthouse -- however, they questioned ... (its) privacy," Choochuey says.
"We responded that this was the first prototype -- the privacy could be improved easily through more layers of fabric that could work in a similar way to a curtain."
Filling in the gaps
In Paris, historic buildings that can't be modified due to French heritage laws have posed their own challenge. Architect Stephane Malka has responded by filling gaps between these structures with glass, steel and wooden structures
that serve as affordable inner-city housing.
Stephane Malka is building in between historic buildings in Paris, where space is tight. Credit: Courtesy Stephane Malka
A similar approach has been taken in Sheffield, England, where a derelict Victorian-era industrial building, 192 Shoreham Street, was revitalized in 2012 when architectural firm Project Orange added a parasitic double-height roof to the structure. It houses a bar and restaurant, plus office units.
Meanwhile, in the United States, a rustic cabin dubbed "Manifest Destiny!", designed by Mark Reigelman and Jenny Chapman, is a bird box-like structure suspended on the side of the Hotel des Arts in downtown San Francisco.
This parcel of space posted in a city where real estate prices have spiraled in recent years was intended as a "commentary on the arrogance of the Westward expansion."
The solution to urban problems?
Cheap to construct. Efficient use of space. Socially inclusive. Parasite architecture seems to be a no-brainer solution to the modern challenges facing many cities.
Furzer agrees: "Architecture, if designed and used correctly can be an empowering tool. It can provide many different elements to one's life, from security to warmth, protection and even a sense of well-being."
The Parisien parasitic structures take advantage of nooks and crannies. Credit: Stephane Malka Architecture
But could legal issues or other problems arise?
Abellanas says that, for the time being, his Spanish studio "has not yet been discovered by the authorities."
"Ownership, leasehold, and land and air rights will have to be substantially reconsidered to support 'parasitic architecture'," CJ Lim, a professor of architecture and urbanism at University College London and author of "Inhabitable Infrastructures: Science Fiction or Urban Future?", tells CNN.
"Legislators are required to have an imaginative mindset."
A rooftop attachment designed by Panos Dragonas and Varvara Christopoulou, shown in this rendering with Athens as a background. Credit: Panos Dragonas, Varvara Christopoulou
He doesn't, however, see parasite architecture as a "wholesale" solution to urban problems.
"These buildings are seeds of innovation to highlight issues of high rents, lack of space and homelessness," he says.
"These projects, and many more innovative projects, can force us to rethink priorities and established dogma.
"Such projects might even force us to rethink legislation."