The studio of French architect Stephane Malka have unveiled the latest iteration of their ‘Parasitic architecture’ concept, with an ambitious plan to graft extensions, bow-windows and loggias to one of Paris’ lacklustre and poorly-performing 1970s buildings.

The project, called Plug-In City 75, will transform an apartment block in the French capital’s 16th arrondissement by ‘plugging in’ custom-made prefabricated elements to the outside of the structure.

Old windows, bad insulation and the presence of heat bridges mean the building’s energy consumption is high, while the flats inside are dark and gloomy. Its co-owners have commissioned Malka to optimise the properties using his own brand of parasitic design – an environmentally-friendly and economical solution to creating living space in urban areas short of space for new developments.

While Paris’ property law has been relaxed to relax planning regulations, particularly for rooftops, it still does not allow the height of buildings to be raised. Therefore, grafting elements to expand outwards is one of the most practical solutions to finding more space.

Each inhabitant has requested the ideal surface area they require for their apartment. The ground floor apartments will be extended outwards, using modular prefabricated boxes built from bio-sourced natural wood and attached to the existing façade of the building.

The top of these boxes will then become a private terrace for first-floor residents.

This pattern of cubes will be repeated up the building, with each differently-sized box allowing for two levels of extension – one covered interior space, and one interstitial terrace, balcony, box garden or loggia for the floor above.

The lightness of the wood, made from wood particles and chips, will allow flexibility when it comes to installing the mini-structures on site.

“The accumulation of extensions on the façade divides the energy consumption of the building by four, down to 45KWh per square metre per year” said Malka. “Thus the building is transformed and adapted to the real needs of its inhabitants.

“Today’s architecture and the mutation of cities must be built on existing heritage. We can ‘para-site’ the city, literally, by leaning back against it, healing its wounds and its heritage in a logic of transformation – using superposition, addition and extension.”

While Malka’s work has mostly been applied to residential projects, the concept has many potential leisure applications. Low-cost music venues, eateries, bars, shops, sports facilities and museums could be brought to busy cities without the need to first tear down old buildings to create space.