Commitment to climate change. FULTON by Ignacio Prego Architectures

Balancing the built/unbuilt ratio

The building’s dense vertical structure frees up floor space and increases natural space.

This allows a larger proportion of greenery, which plays an essential role for comfort in summer.

This extensive use of plants is formalised through dense planting of tall trees on the ground floor and the positioning of green terraces on the upper floors.

These elements not only help to improve building insulation, but also help to combat the effects of the urban heat island.

The plants create filtered shade over the buildings and people, the planted areas naturally soak up humidity and contribute to the plants’ evapotranspiration process, significantly reducing air temperature at the heart of this open plot.

One of the other issues relating to the floor ratio is the limitations linked to the proximity of the Seine. Also, whilst the waterproofing of cellars and elevation of garden areas reflect the site’s classification as a PPRI (Flood Risk Prevention Plan) area, these arrangements also anticipate one of the short-term consequences of climate change: a larger number of rainfall events, more intense rainfall, and the subsequent flooding.

The use of natural areas and planted roofs also reflects this initiative, and allows optimised retention of rainwater to limit run-off rates. However, these systems cannot be viable in the longterm without making them easy to maintain.

In this regard, we have prioritised planting the ground floor areas and roof terraces in non-accessible communal areas to guarantee professional maintenance of these spaces.

The planting of trees and nesting boxes in these protected areas not visited by residents helps protect local bird species and, with a goal to free up roof spaces and create a biodiversity haven, is part of the green infrastructure developed in the heart of Paris.

Eliminating excessive sun exposure

One of the significant and unique features of this project is the systematic use of moving sun protection on all windows, allowing residents to adjust sun exposure depending on their preferences.

Perforated aluminium external shutters, designed like mashrabiya-style lattices, are used on the balconies. They form a large sun shade which limits building heat without impacting visual comfort. Thanks to their configuration, they offer a sufficient level of natural ventilation even when closed, and act as a true ventilated plenum. Also, with 50% of the façade’s linear area protected by the edges of deep long balconies, the outdoor spaces help control sun protection by forming a brise-soleil.

Our design also focused on differentiating between the types of opening. Bay windows are only located at the base of the balconies, where they are naturally protected. On the outer façades, the bay windows are surrounded by 60 cm frames which form a protruding profile and limit the sunlight entering the apartments. This system is a modern interpretation of the thick frames employed in traditional Mediterranean architecture. The light coating on the façades helps passively cool the buildings, limiting overheating due to excessive absorption of the sun’s rays in summer, whilst offering constant brightness in winter thanks to the light reflection potential.

Cooling the air temperature

Thanks to the use of external insulation, the thermal inertia of brick walls and floors is harnessed to store cool air at night and release it during the day. This is an important system to considerably limit the rise in temperature inside housing units.

Also, the double and even triple-facing housing creates the ideal conditions for natural ventilation at night.

Diversifying the external surfaces of the housing helps limit distribution of the sun's rays in this way, whilst preserving quality natural lighting inside the homes.

By combining thermal inertia with the different sun protection systems mentioned above, residents are able to control their home’s temperature more effectively thanks to simple and efficient processes.

At night, residents open their windows to air out the room and cool the wall and floor masses thanks to the drop in temperature at night. During the day, they lower the shutters and close the windows to limit sun exposure and above all to retain the cool air stored at night.

Based on this user scenario, we recorded a difference of 12.5° between the indoor temperature maintained at 28.5°, whilst the outdoor air rose to 41° in the late afternoon.

Previously considered mild, the rapid and radical change in temperatures requires a response that reflects this major paradigm shift.

This project demonstrates architecture’s ability to offer simple and effective systems to tailor buildings able to offer a passive environmental response to this new challenge, which is as urgent as it is exciting for our generation of architects.

Whilst climate change has far from peaked in Paris, temperatures have already risen considerably. The average temperature in Paris in 2022 (14.3°C) has exceeded Rome’s average temperature for the 1951-1980 period (14.0°C), with a remarkably similar spread of summer temperatures.

By using appropriate strategies and tools, we can minimise the warming of homes with a passive and energy-efficient approach.

In order to acknowledge the direct and concrete effects of using these strategies, during the last heatwave (summer 2022) we analysed temperatures measured outdoors (at 8am, 4pm and midnight) and temperatures measured inside the homes at the same time.

By using the “free cooling” method - which involves harnessing favourable outdoor conditions by opening windows at night to allow outdoor air to circulate inside, in order to cool indoor spaces by removing heat accumulated during the day - we can see a difference of -10 to -12.5°C between the indoor and outdoor temperatures.

This is an effect similar to air conditioning.