Spanish architecture studio Takk has pulled back the walls of an apartment in Madrid to create an outdoor terrace alongside an insulated space that contains a bedroom on stilts.
Takk removed all of the 110-square-metre flat's interior walls to create a new 60-square-metre space enclosed with insulated pinewood walls, dubbed the winter house.
This space contains an open-plan kitchen and living room as well as a self-enclosed bedroom perched on stilts, which is designed to be shared by a couple and their young daughter.
Both the bedroom and the flat's new exterior walls are made from low-carbon, heat-retaining materials, with pinewood frames sourced from Spain's famed winemaking region of La Rioja and insulation made from duvets and charred cork.
Takk nested the spaces in the winter house inside each other like the "layers of an onion" to retain heat and conserve energy during the colder months.
Alongside the apartment, the studio created an exterior terrace by relocating the external walls and removing the previous north-facing windows.
Named the summer house, this space is connected to the inner areas of the home by sliding glass doors.
According to the studio this arrangement eliminates the need for air-conditioning by passively cooling the interior and helping to lower the apartment's carbon emissions in operation.
"Climate change will modify all the routines of our existence," Takk co-founder Mireia Luzárraga told Dezeen. "The way we think and build our environments should also adapt to this new situation."
"The project tests possible ways of organising a house to minimise energy consumption while using materials with a low carbon footprint."
From the outside, the door leading to the apartment looks like any other in the residential block. But on the interior of the flat, the entrance is hidden inside a built-in shelving system that runs along one side of the winter house.
A similar storage wall is mirrored on the other side of the open-plan space, forming a low counter that functions as a kitchen worktop on one side and a dining table and work desk on the other.
Like most surfaces in the winter house, this is almost entirely clad in blackened cork panelling, which stores carbon and holds onto heat in the winter due to its colour and porous structure.
In contrast, the summer house external space is finished with cement mortar, which doesn't hold onto heat from the sun during the warmer months.
This outdoor area consists of a narrow plant-filled porch that runs along the apartment's entire north-facing wall to maximise natural light.
At one end, it opens up into a covered terrace, separated from the interior by a pinewood wall with a row of tall vertical vents that can be opened to create a through-draft.
In summer, the space can be shielded from the sun by an aluminium-foil thermal curtain normally used in greenhouses, while folding glass doors allow it to be turned into a kind of winter garden once temperatures drop.
On the other side of the folding doors lies a balcony housing a speckled bathtub, which is shielded from view only by a sheer pink gossamer curtain.
This bathroom is designed to be used only in summer and by multiple members of the family at the same time, much like the open-plan living area and bedroom.
"The aim is to test the benefits, both energetic and emotional, of sleeping, playing or working together," said Takk's other half Alejandro Muiño.
"In the past, rooms used to be bigger because they were communal and easier to heat. We want to recover this popular knowledge that was forgotten due to the emergence of cheap energy."
The stilted bedroom is the warmest part and the centrepiece of the home contained within the cork-panelled winter house and fitted with an extra layer of insulation in the form of duvets.
These are strapped to the outside of the pinewood box alongside garlands of fake flowers, while huge stones from a quarry outside Madrid dangle from the ceiling, acting as a structural counterweight to prevent the thin wooden panel from bending.
On the inside, the bedroom is entirely panelled in pinewood and split over two levels.
"The advantages of sleeping together are countless, both for climatic and energy-saving reasons and for the reinforcement of emotional links," Takk explained.
"Elevating the bedroom also allows the kitchen to be more present in the daily routine of the residents because it is visible from any part of the house, which helps fight the gender and class cliches associated with these kinds of spaces."
Although elevated rooms such as this are rarely found in interiors, a number of architects have raised entire homes up on stilts in a bid to tread lightly on their surrounding environment.
Dezeen has rounded up 10 of the most impressive examples, from a cork-clad cabin above a tidal salt marsh to a summer house perched on the rocky edge of a Norwegian island.
The photography is by José Hevia.