Construction and renovation

Key solutions

• #1 Renovation rather than construction

  Renovation allows the reuse of many of the elements of a building, such as its roof, walls and structure. It also reduces the use of new materials and the energy consumption associated with their use. Renovation also reduces demolition waste and avoids the occupation of new natural areas.

• #2 Conception and design

  Designing buildings to take into account local climatic conditions, particularly orientation to the sun and prevailing winds, and make the most of them. The orientation of buildings will reduce or increase heat gain depending on the context. Natural ventilation and lighting should be favoured to minimise energy consumption, particularly for lighting and air conditioning.

• #3 Drainage wells

  Constructing a drainage well, also known as a Canadian well or Provencal well, is a natural way to heat and cool the interior of buildings without impacting the environment, simply by using outside air. Outside air is drawn into one or more ducts buried horizontally in the ground beneath or adjacent to the building, at least 1.5 m deep. This air picks up the coolness of the ground in summer and the heat of the ground in winter, and then diffuses it inside the building once it has left the ducts.

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• #4 Trombe wall and solar chimney

  Installing a Trombe wall reduces energy requirements for heating. The Trombe wall is a passive solar heating system that consists of a solid, darkly painted, south-facing (in the northern hemisphere) wall with a glass pane in front of it. This glass traps the sun’s heat (greenhouse effect), which accumulates and diffuses through the wall to the interior. Solar chimneys, coated in black and facing south, absorb the heat from the sun’s rays and diffuse it into the indoor air.

• #5 White roofs

  Painting the roofs white reflects the sun’s rays and thus prevents heat from being transmitted into the building. This significantly reduces the need for energy-intensive air conditioning. This is a simple, inexpensive and effective solution that does not require major work. Some insulating and reflective paints further enhance the result. (“Cool Roof”)

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• #6 Protection of windows

  The use of adhesive films on windows (or glass) will reflect the sun’s rays and prevent the transmission of heat into the building. Fixed or mobile sunshades will shade the most exposed windows and reduce the effects of overheating inside buildings.

• #7 External insulation

  Insulating from the outside means installing a layer of insulation on all the facades of a building. The insulation will act as a thermal envelope and protect the premises from heat or cold. Placed on the outside of the walls, the insulation prevents heat leakage (thermal bridges) and contributes to better heat storage by the walls (thermal inertia). Insulation from the outside therefore makes it possible to limit rapid variations in interior temperature, and to make significant energy savings without impacting on the occupiable surface area of the buildings.

• #8 Green Building

  Greening roofs and facades improves the thermal insulation of buildings and saves energy by reducing the need for air conditioning. In addition, the water vapour produced by the plants cools the ambient air and reduces the urban heat island effect.

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• #9 Tree planting

  Planting trees near buildings cools the air through evapotranspiration from the foliage and reduces urban heat island effects. In addition, trees store carbon, improve air quality and provide shade. It is important to plant endemic, non-invasive, varied species that are, if possible, interesting for local biodiversity. Existing natural areas should be preserved. Others can be restored.

• #10 Materials with high thermal inertia

  Use materials with high thermal inertia, i.e. materials that store heat, or cold, and release it gradually into the room. Thermal inertia slows down the speed of heat propagation through a wall and helps to maintain a constant temperature inside a building. Materials such as earth, brick or stone have a high thermal inertia.

• #11 Biobased materials

  Preferably use biobased materials from biomass, such as wood, reed or sheep’s wool, as well as geobased materials of mineral origin, such as earth or stone. These materials generally have a low environmental footprint when they are local and minimally processed. However, the methods of extraction or collection can have a significant impact on the environment.

• #12 Reused materials

  Using materials from reuse or waste reclamation, in particular demolition waste, is an alternative to extracting new raw material. In addition, reuse often limits transport and reduces the volume of waste to be landfilled. Materials are given a second life without undergoing major transformation and are thus part of a circular economy system.