Embodied carbon in construction is the greenhouse gas emitted to extract, manufacture, transport and assemble a building’s materials, before anyone switches on a light. It’s distinct from operational carbon, the emissions from running the building later. And it matters more than many teams assume, because most of it is committed early, by material choices made before a formal assessment ever begins.
That early window is the point of this guide. Material decisions taken at concept and scheme stage lock in a large share of a project’s whole-life carbon. Once steel is ordered or a slab is poured, those emissions are spent. So the highest-leverage moment to act is also the moment with the least structured information, which is exactly the gap worth closing.
The short version
- Embodied carbon is the emissions from making and moving materials; operational carbon is from running the building. This guide is about the former.
- The buildings and construction sector accounts for ~37% of global energy- and process-related CO₂ emissions (UN Environment Programme).
- As grids decarbonise, embodied carbon becomes a larger share of whole-life carbon (World Green Building Council, 2019).
- Early material decisions commit most embodied carbon. Refurbishment and reuse usually beat new build, because retained material carries almost no new emissions.
- You can compare strategies before a formal LCA using indicative impact classes and circularity pathways. These are for comparison, not certification or compliance.
What is embodied carbon?
Embodied carbon covers the emissions from a material’s production chain: extraction, manufacturing, transport and on-site assembly, measured in kg CO₂e. In the EN 15978 life-cycle structure, everything emitted up to handover is modules A1–A5 (upfront carbon), with maintenance, replacement and end-of-life counted in later modules. Embodied carbon is the front-loaded part, spent before occupation and largely fixed once the material is in place, which is why the decision sequence matters so much.
Operational carbon, from running the building, is the other part of whole-life carbon; the embodied vs operational carbon comparison covers how the two differ.
Why does the split keep shifting toward embodied carbon? As operational energy decarbonises, embodied (upfront) carbon becomes a larger share of whole-life carbon (World Green Building Council, “Bringing Embodied Carbon Upfront”, 2019). A building running on renewable electricity still carries the full emissions of its concrete, steel and insulation. The cleaner the grid gets, the more the materials dominate the total.
Why does construction’s carbon footprint matter at this scale?
The buildings and construction sector accounts for around 37% of global energy- and process-related CO₂ emissions (UNEP, Global Status Report for Buildings and Construction 2025-2026). That figure spans both operational and embodied sources across the built environment. It places construction among the largest single contributors to global emissions, which is why material strategy is no longer a niche concern.
For a project team, the scale translates into leverage. A meaningful share of those emissions is embodied, and a meaningful share of the embodied portion is decided at the drawing board. Structure and envelope, the heaviest, most carbon-intensive elements, are specified first and changed least. That early concentration of impact is the reason this guide focuses on the decision moment rather than the as-built outcome.
Why do early material decisions lock in most of the carbon?
Most embodied carbon is committed during early design, when the structural system, envelope and primary materials are chosen, often before any formal life-cycle assessment runs. By the time a certified LCA confirms the numbers, the high-impact choices are usually settled. The assessment then measures decisions already made, rather than shaping them.
This is the awkward part. The moment with the most influence over carbon is also the moment with the least structured data. Teams reach for scattered datasheets, rules of thumb and memory, then commission rigorous analysis once the design is fixed. The order is backwards from a carbon-reduction point of view, and closing that gap is precisely where pre-assessment comparison helps.
A practical response is to treat early-stage numbers as indicative and comparative, not as compliance figures. You don’t need a certified result to know that a retained slab carries far less new carbon than a replacement, or that a cubic metre of steel sits in a higher impact class than a cubic metre of concrete. Directional clarity, available early, is enough to steer the big decisions. For more on this stage, see pre-assessment material intelligence.
New build or refurbishment: how does the split change the carbon question?
New build and refurbishment are different carbon decisions, and conflating them leads to weaker choices. On a new build, almost everything is new material, so the carbon question is which material, which system, which alternative. On a refurbishment, much of the structure already exists, so the question becomes what can we keep, and retention is usually the single biggest saving available.
Retained material carries almost no new embodied carbon, because the emissions of producing it were spent long ago. That makes “keep it” the strongest move on most existing buildings, ahead of even the cleanest new specification. The deeper trade-offs, when to retain versus rebuild, are covered in refurbishment vs demolition and reusing building elements vs new.
The two contexts also need different inputs. A new build starts from a design brief and quantities; a refurbishment starts from a survey of what’s already there. Both can begin from existing data: importing an existing building from IFC or DXF lets a team classify each element by its retention potential before deciding anything.
How can teams compare options before a formal LCA?
You can compare material strategies before a certified LCA by using indicative impact classes and circularity pathways, both designed for early comparison rather than compliance reporting. They turn scattered data into a structured, side-by-side view. The numbers are directional, grounded in published generic datasets, and explicitly not a substitute for formal assessment.
This is the layer Elementa works in. Two concrete examples follow: a classification of how carbon-intensive a material is, and a factor for how much carbon a given lifecycle decision retains or spends. Both are reference-based, meant to inform the conversation that happens before commitment.
Indicative impact classes
Impact classes band materials by embodied-carbon intensity so you can read relative impact at a glance. Elementa prices each layer from an ÖKOBAUDAT generic dataset (EN 15804+A2, modules A1–A3) pinned to that layer, proposing the dataset that fits the project’s location first, generic before product-specific, and asking you when several fit equally. A layer with no dataset pinned stays unpriced and is left out of totals rather than given a default figure. The bands are deliberately coarse, because the goal is early comparison, not a precise figure.
| Impact class | Range (kg CO₂e/m³) |
|---|---|
| Low | below 200 |
| Medium | 200–800 |
| High | above 800 |
Impact classes are computed per cubic metre (carbon × density), not per kilogram. That is why concrete reads Medium despite a small per-kilogram figure: its density is what makes it a large carbon source. A material with no density shows no class rather than a guess.
Treat these classes as indicative, for comparison, not for certification or compliance. They help a team see that one specification sits in a different band from another, early enough to act on it. How generic datasets compare with product EPDs is covered in EPD vs generic dataset, and how classes guide substitutions in material alternatives and impact class. The ICE Database, a widely used reference dataset that Elementa does not use, is explained in the ICE Database explained.
Circularity pathways and their carbon factors
Circularity pathways describe what happens to an element across its lifecycle, from keeping it to replacing it entirely. Each pathway carries a carbon factor applied to the element’s baseline embodied carbon, so retaining something scores far lower than building it new. The factors below run from most to least circular.
| Pathway | Meaning | Carbon factor (× baseline) |
|---|---|---|
| Retain | Keep in place, maintain as-is | 0.05 |
| Reuse | Relocate or repurpose on-site | 0.15 |
| Refinish | Re-surface, re-coat, restore | 0.40 |
| Replace | Swap with new equivalent | 1.10 |
| New | Entirely new material (baseline) | 1.00 |
These factors are Elementa’s own modelling conventions for early comparison, not drawn from ÖKOBAUDAT or any published dataset. The material carbon values behind a baseline come from the ÖKOBAUDAT dataset pinned to each layer; these multipliers do not. The factors describe carbon only: pathways carry no cost percentage.
The pattern is clear: the more you keep, the less new carbon you spend, and often the less you pay. A retained element carries roughly 5% of the embodied carbon of building it new, which is why retention dominates on refurbishment. These factors are indicative, for early comparison only, not certified figures. The full logic is in circularity pathways.
How can a team act early, in practice?
Acting early means structuring the material decision before it’s committed, then refining with formal assessment later. The sequence is straightforward: capture quantities, assign pathways, compare strategies, and use the comparison to align designers, developers and investors. None of this replaces a qualified LCA; it informs the choices that the LCA will eventually measure.
A workable order looks like this:
- Capture quantities from a design brief (new build) or a survey (refurbishment), importing existing buildings via IFC or DXF where possible.
- Assign a pathway to each element: choose specifications for new build, or classify retain / reuse / refinish / replace / new on an existing building.
- Compare strategies by indicative impact class, circularity pathway and, where the cost reference covers an assembly, indicative cost, side by side.
- Commission formal assessment once the direction is set, against the RICS Whole Life Carbon Assessment methodology (RICS) or equivalent, with a qualified professional.
The point of steps one to three is to reach step four with the high-impact decisions already pointed the right way. Cost belongs in the same view, because circularity and budget often pull together rather than apart. Elementa estimates it per assembly from a versioned 2026 Austrian reference of expert estimates, for early comparison and not for tendering; how that works, and where ÖNORM B 2061 fits, is unpacked in cost and circularity.
Frequently asked questions
Is embodied carbon the same as a building’s carbon footprint?
No. A building’s footprint is its whole-life carbon, which includes embodied carbon (from materials) plus operational carbon (from running it) and end-of-life emissions. Embodied carbon is the upfront, material-related part. As grids decarbonise, it becomes a larger share of the total (World Green Building Council, 2019).
Does refurbishment always beat new build on carbon?
Usually, but not always; when it doesn’t, and how to tell element by element, is covered in refurbishment vs demolition.
Are indicative impact classes accurate enough to rely on?
They’re accurate enough to compare, not to certify. Impact classes are computed per cubic metre from the ÖKOBAUDAT dataset pinned to each layer, and pathway factors are Elementa’s own modelling conventions; both are built for early decision support. They are not for certification, compliance, or official reporting. For those, commission a formal assessment with a qualified professional.
Where this leaves you
Embodied carbon in construction is decided early, concentrated in the heaviest elements, and difficult to undo once construction begins. The sector’s scale, around 37% of global energy- and process-related CO₂ emissions (UNEP), makes the material decision consequential. And because retained material carries almost no new carbon, the question “what can we keep” is often the most powerful one a team can ask.
The practical takeaway is to bring structure to that decision before commitment, using indicative classes and circularity pathways for comparison, then formal assessment to confirm. Elementa is built for exactly that pre-assessment moment, on new build and refurbishment alike. Start a project or book a demo from the homepage.