The property professionals’ solution

The real estate sector generates 21% of global greenhouse gas emissions. In 2022, buildings accounted for 34% of global energy demand and 37% of energy-related CO₂ emissions.

The main source of emissions comes from construction materials, particularly concrete and steel. Concrete alone is responsible for around 7.5% of global emissions, mainly due to cement production, its most carbon-intensive component.

Concrete in Switzerland

Switzerland consumes around 1.3 m³ of concrete per capita per year, more than twice the European and global average. Cement, the main component of concrete, accounts for 65% of the emissions generated during the production of one cubic metre of concrete. In 2019, concrete represented 82.3% of the construction materials used in Switzerland. This high dependence makes its carbon footprint incompatible with the 2050 climate targets, despite its central role in the sector.

Beyond its carbon footprint, concrete causes increasing problems linked to the extraction of its raw materials. Limestone, clay, and aggregates are limited resources whose availability decreases as construction activity intensifies. In Switzerland, pressure on gravel pits leads to resource scarcity, land-use conflicts, and significant impacts on biodiversity.

Low-carbon building materials

Low-carbon building materials make it possible to reduce CO₂ emissions over the entire life cycle of buildings. They have low embodied energy because their production and transport require less energy and incorporate more renewable resources. They often contain recycled materials and are themselves recyclable, which supports the circular economy. Their durability reduces the frequency of replacements, and their local origin limits transport-related emissions. In Switzerland, their use is essential to achieving carbon-neutrality targets.

A wide range of ecological materials is available, particularly:

• wood for load-bearing structures;
  
• rammed earth and compressed earth blocks for walls;
  
• clay and lime for surface finishes;
  
• bio-based insulation materials such as lime-hemp mixes, sheep’s wool, cellulose, wood fibres, straw, or grass.

Low-emission concrete: strategies for reducing emissions

Several approaches make it possible to reduce the carbon footprint of concrete while maintaining its essential structural properties.

Reduction of cement content:The integration of cementitious additives (silica fume, fly ash, blast furnace slag, recycled glass powder) reduces the required amount of clinker, which is the main source of emissions. Using these additives can reduce the carbon footprint of concrete by around 20%, while maintaining mechanical performance.

Optimisation of mix design and production chain:Cement dosages vary considerably between producers, even for similar strength classes. Better coordination between stakeholders (manufacturers, engineers, and construction companies) could reduce the amount of cement used by up to 30%, thanks to formulations tailored to the actual requirements of each structure.

Economic incentives:Low-carbon concretes are generally more expensive and sometimes require longer processing times. Incentive or compensation mechanisms are needed to support their adoption despite the economic challenges faced by companies.

Technological innovations:New solutions enhance decarbonisation potential, such as LC3 cement (developed at EPFL), which greatly reduces the clinker content, or 3D-printed concrete, which requires less material and enables optimised geometries. These innovations pave the way for even greater emission reductions.

Although concrete cannot be completely replaced in the short term, these strategies significantly reduce its environmental impact while gradually enabling the development of more sustainable alternatives.

Materials Transforming the Construction Industry

The construction sector is undergoing a profound transformation driven by innovative materials combining technical performance, environmental sustainability and circular economy principles. These new solutions are reshaping the way we design homes, commercial buildings and infrastructure by offering greener, lighter and more climate-adapted alternatives.

TimberRoc: wood-based concrete with a negative carbon footprint

Made from wood aggregates, water and cement, with no petrochemical additives or synthetic fibres, TimberRoc concrete marks a major step forward in bio-based construction materials. Factory-produced to ensure consistent quality, it arrives on site ready to install.

Use: Ideal for load-bearing walls in single-family homes, multi-unit housing or tertiary buildings. TimberRoc combines the benefits of CLT (cross-laminated timber) with those of high-performance lightweight concrete: excellent fire resistance, strong thermal inertia (up to 17 h of phase shift) and very good acoustic absorption (αw = 0.7).

Hemp–lime block: an insulating and regulating material

Made from hemp, dolomitic air lime, probiotics and water, this material captures more CO₂ over its lifetime than it emits, making it exemplary from an environmental perspective.

Use: Applied to the building envelope, it is compatible with wood, reinforced concrete or steel structures. It is also used for roof, attic and ceiling insulation, interior partitions that regulate temperature and humidity, and to enhance thermal and acoustic comfort.

Remetter wood–clay slab: a Swiss alternative to reinforced concrete

Developed in Switzerland, Remetter slabs combine solid wood beams with fired-clay infill. Assembled dry or screwed, they fit perfectly within a circular-economy approach.

Use: They efficiently replace reinforced-concrete floors thanks to massive CO₂ reduction, excellent moisture regulation, high thermal inertia and good sound absorption provided by clay.

Gramitherm: grass-based insulation with a negative carbon footprint

Made from grass fibres, recycled jute and synthetic binders, Gramitherm stands out for its regenerative nature: grasses grow rapidly and are often recovered from waste sources such as roadsides or gardens.

Use: Suitable for interior or exterior insulation, it protects against cold, regulates humidity, absorbs sound and provides a thermal conductivity of 0.027 W/m·K at 150 mm thickness.

Cross-laminated timber (CLT): the new generation of structural wood

CLT panels are composed of 3 to 11 layers of wood arranged crosswise and glued together. Renewable, durable and structurally strong, they enable the construction of tall or complex buildings with a low environmental impact.

Graphene: a material with limitless potential

Made from a single layer of carbon atoms, graphene is ultra-conductive, extremely light and exceptionally stable. Applications include structural reinforcement, integrated heating systems, improved batteries, smart coatings and ultra-resistant composites.

Hempcrete: lightweight, insulating and ecological

A mixture of sand, lime and hemp fibres, hempcrete is available as blocks or can be poured directly on site.

Use: lightweight and well-insulating bricks, natural CO₂ absorption during curing, excellent thermal and acoustic regulation.

Transparent concrete: concrete that transmits light

By incorporating fibre optics, this concrete lets natural light pass through while maintaining mechanical strength. Still rarely used, it opens the door to innovative façades and interior spaces.

Use: shower walls, staircases, luminous façades, decorative interior walls.

Recycled plastic tiles: lightweight and fast to install

Made from recycled plastic waste, these tiles are extremely light (up to 7× lighter than conventional tiles), weather-resistant, durable and economical in transport.

Smart glass: glazing that adapts to light

Electrochromic glass changes its tint through low electric voltage and lithium-ion transfer. A control software adjusts the level of tint according to exterior light.

Benefits: reduced energy costs, improved indoor comfort, automatic glare management.

Phase-change materials (PCM): storing and releasing heat

PCMs absorb heat when they melt and release it when they solidify. They help reduce cooling needs by up to 30 %, stabilize indoor temperatures and increase overall energy efficiency.

Good reasons for sustainable renovation or construction

Three main arguments justify the use of sustainable building solutions:

Reduction of greenhouse gas emissions:Recycled or low-embodied-energy materials (wood, brick, unfired earth) generate fewer emissions during their production. The use of local resources also reduces transport, and wood additionally stores CO₂ over the lifetime of the building.

Support for the local economy:Investments in sustainable construction strengthen regional employment, especially in renovation activities, which offer strong market potential. They also help reduce operating costs and improve the value stability of buildings.

Resource conservation:Sustainable construction optimises the use of resources over the entire life cycle of the building (planning, construction, operation, renovation, and deconstruction), reducing environmental impacts and improving the quality of the built environment.

Advantages of sustainable construction

• Preserves and improves urban quality.
  
• Ensures healthy, safe, and comfortable buildings.
  
• Provides sustainable infrastructures and services.
  
• Stabilises and strengthens the value of buildings and infrastructure.
  
• Improves the competitiveness of the Swiss construction and real estate sector.
  
• Reduces costs over the entire life cycle of the building.
  
• Contributes to the protection of nature and biodiversity.
  
• Limits impacts on soil, water, air, and climate.
  
• Promotes social cohesion.
  
• Creates the conditions necessary for implementing the energy strategy and achieving climate goals.

Macroeconomic context

Sustainability is advantageous from a macroeconomic perspective, as climate change exerts increasing pressure on infrastructures and physical assets. The real estate sector is particularly exposed to these effects.

The main problem lies in the increase in physical risks that directly affect the building stock. Extreme temperatures, heavy rainfall, floods, and droughts accelerate the degradation of materials and structures. This manifests particularly in increased cracking, water infiltration, thermal deformation, and faster wear of building technical systems.

These physical impacts lead to measurably higher costs for owners and operators:

• more frequent maintenance costs,
  
• earlier renovation interventions,
  
• necessary structural reinforcement in certain regions,
  
• and rising insurance premiums due to more frequent damage events.

Assets located in areas with high climate risk may also suffer a loss of value due to reduced attractiveness, usage restrictions, or higher operating costs. In this context, reducing the use of concrete becomes increasingly meaningful.

Conclusion

The adoption of low-carbon building materials and sustainable construction methods is progressing rapidly due to climate targets, regulatory requirements, and the need to reduce the environmental footprint of the built environment. This structural shift is concretely transforming sector practices and establishing new technical standards for the coming years.

Sources

nnbs.ch - Article
publication.vd.ch - Article
lutz-architectes.ch - Article
frilow.ch - Article
espacescontemporains.ch - Article
batiweb.com - Article