Climate-friendly material choices in construction
Why the same material can have very different carbon footprints
When a building's climate footprint is to come under the Building Regulation's limit values, material choice is often where the biggest effect is achieved. Materials typically account for a large part of a building's total climate load, even before the building is used at all.
§Biogenic and mineral materials
Building materials are often divided into two main groups in a climate context. Biogenic materials such as wood straw and other plant-based materials have absorbed CO2 from the atmosphere while they grew and can therefore under the right conditions have a lower or even temporarily negative climate footprint in the production phase. Mineral materials such as concrete and brick typically require more energy to produce and emit CO2 directly in the production process among other things from cement production.
- 01Biogenic materials: wood, straw and other plant-based building materials
- 02Mineral materials: concrete, brick and other materials based on extracted raw materials
- 03Metals: steel and aluminium, which often have a high footprint in production but can be recycled many times
- 04Insulation materials: can be both mineral-based and biogenic, with very different impacts
§The same material can vary greatly
It is a misunderstanding that one material is always 'the green choice'. Two suppliers of the same material can have very different carbon footprints, depending on which energy source their production uses, how efficient the process is, and how far the material is transported to the construction site. This is exactly why product-specific EPDs are so important — they show the actual footprint for the specific product you are considering using, instead of an assumption based on material type alone.
§Reuse and longevity also count
Climate footprint is not just about material manufacturing but about its entire lifespan. A reclaimed brick lot or reused steel structure can have significantly lower footprint than new material because the production phase has already been 'paid for' earlier. Materials that last long and can be maintained also reduce the need for replacement and thus new material consumption over the building's lifespan.
§How it is included in BR18's calculation
When a project's LCA is to meet the Building Regulation's limit values, material choice becomes a direct part of whether the project passes or not. A project that chooses more biogenic materials, recycled components, or products with documented low impact via product-specific EPDs often stands stronger in the calculation than a project based solely on traditional material choices and generic data.
- 01Consider bio-based alternatives where the construction allows
- 02Explore the possibilities for used or recycled materials.
- 03Prioritize materials with product-specific EPDs for climate-controlled projects
- 04Remember that durability and long service life are also a climate advantage
For craftspeople and purchasers it means material choice is no longer just about price strength and availability — the climate footprint has become a fourth factor that increasingly weighs in when a project must meet the rules.
§Renovation versus new construction
Climate accounting applies mainly to new construction, but the same principles are relevant for renovation. Preserving and reusing an existing building structure instead of tearing down and building new often avoids much of the climate footprint that would otherwise arise from manufacturing new materials. Therefore, a thorough assessment of whether something can be preserved, repaired or upgraded is often the first and most climate-friendly question — before the choice between different new materials even comes into question.
§Indoor climate and material selection are related
Climate-friendly material choices must not be viewed in isolation from other considerations such as indoor climate, moisture conditions and durability. A biogenic material that is not properly protected against moisture can have a short lifespan and thus still end up with a higher overall climate footprint because it needs to be replaced more often. The good material choice is therefore always an overall assessment of climate footprint, function and durability together — not an isolated hunt for the material that looks best in a single calculation.