Circularity pathways are five ranked choices for what to do with each building element: Retain, Reuse, Refinish, Replace, or New. Each pathway carries an indicative carbon factor applied to the element’s baseline embodied carbon, running from Retain at 0.05× up to New at 1.00×, plus a rough cost direction. Assigning a pathway to every element early in a project is one of the most direct ways to steer its carbon and cost, before any formal assessment is commissioned.
These factors are indicative, for comparison only. They are not certified figures, and they are not a substitute for a formal life-cycle assessment.
The short version
- Five pathways, most to least circular: Retain, Reuse, Refinish, Replace, New.
- Carbon factor (× baseline): Retain 0.05 · Reuse 0.15 · Refinish 0.40 · Replace 0.70 · New 1.00.
- The cheap move and the green move usually agree: keeping what’s already there tends to cut both carbon and cost.
- Pathways are a decision tool, not a calculation. They orient a conversation before formal assessment, not replace one.
- As operational energy decarbonises, embodied carbon becomes a larger share of whole-life carbon (World Green Building Council, “Bringing Embodied Carbon Upfront”, 2019) — which makes early material choices matter more.
Why pathways, and why early?
The buildings and construction sector accounts for roughly 37% of global energy- and process-related CO₂ emissions (UNEP, Global Status Report for Buildings and Construction 2025-2026). A large and growing share of a single project’s footprint is embodied carbon, locked in by material decisions made long before a structural calculation or a certified LCA is run.
That’s the problem circularity pathways address. Instead of treating every element as a fresh specification, you ask a simpler question first: does this element need to be new at all? A pathway is the answer to that question, applied element by element.
Pathways work best when assigned early. Once demolition is scheduled or a specification is locked, the cheapest and lowest-carbon options are often already off the table.
What does each pathway mean in practice?
Each of the five pathways describes a real decision about an element, and each carries an indicative carbon factor multiplied against that element’s baseline embodied carbon. Retain keeps roughly 95% of embodied carbon in place (factor 0.05); New assumes the full baseline (factor 1.00). The factors below are Elementa’s defaults for early comparison, not certified values.
Retain — keep it in place
Retaining means the element stays where it is and keeps doing its job, with maintenance at most. A structural slab, a load-bearing wall, an existing staircase: if it’s sound, retaining avoids almost all of its embodied carbon. Carbon factor 0.05. Indicative cost delta −60% to −35% versus replacing it new.
Reuse — relocate or repurpose
Reuse means the element is recovered and used again, relocated on-site or repurposed for a different function. Think of bricks taken from a removed partition and laid elsewhere, or steel sections cut and refitted. There’s some processing and handling, so the factor is higher than Retain. Carbon factor 0.15. Indicative cost delta −40% to −20%.
Refinish — restore the surface
Refinish keeps the substrate and renews the surface: re-sanding a timber floor, re-coating a facade, restoring joinery. The bulk of the material stays; only finishes are added. Carbon factor 0.40. Indicative cost delta −25% to −10%.
Replace — swap for a new equivalent
Replace means removing the existing element and fitting a new one of the same type. You carry the full carbon of the new material but, depending on labour and demolition, the cost can land close to baseline or above it. Carbon factor 0.70. Indicative cost delta ±0% to +15%.
New — entirely new material
New is the baseline: a fresh element with no existing material carried forward. It’s the reference everything else is measured against. Carbon factor 1.00. Cost is the baseline.
How do the five pathways compare?
The table below sets out all five side by side. Read the carbon factor as a multiplier on an element’s baseline embodied carbon, and the cost delta as an indicative range versus building that element new. Both are for early comparison, not certification.
| Pathway | What it means | Carbon factor (× baseline) | Indicative cost delta |
|---|---|---|---|
| Retain | Keep in place, maintain as-is | 0.05 | −60% to −35% |
| Reuse | Relocate or repurpose on-site | 0.15 | −40% to −20% |
| Refinish | Re-surface, re-coat, or restore | 0.40 | −25% to −10% |
| Replace | Swap with new equivalent material | 0.70 | ±0% to +15% |
| New | Entirely new material (baseline) | 1.00 | baseline |
Two patterns stand out. First, the carbon and cost columns mostly move together: the most circular pathways are also, in the early ranges, the cheaper ones. Second, the gap between Retain and New is large, which is why a project’s pathway mix matters so much. These ranges sit alongside Elementa’s indicative impact classes from the ICE Database (Low, Medium, High by kg CO₂e/kg), which describe the material itself rather than the lifecycle decision.
A worked example: classifying a refurbishment
Picture a mid-century office floor being refurbished. You walk the space and assign a pathway to each element category, using the same logic Elementa applies. None of this is a calculation yet; it’s a structured first pass to orient the strategy.
- Structure — the concrete frame and floor slabs are sound. Retain (0.05). This is where most of the building’s embodied carbon lives, so keeping it dominates the result.
- Envelope — the facade is single-glazed and underperforming thermally. Replace (0.70) for the glazing units; the masonry behind them is fine to Retain.
- Finishes & Surfaces — the timber flooring is worn but solid. Refinish (0.40) rather than rip it out.
- Fixtures & Joinery — existing partition walls are demountable and in good condition. Reuse (0.15), relocated to suit the new layout.
- Furniture & Lighting — lighting is dated and inefficient. New (1.00) LED fittings.
- Textiles & Comfort — acoustic panels are stained. Refinish (0.40) where possible, New where not.
Notice what happened. By retaining the structure, the heaviest carbon category is settled at 0.05× before any other decision. The Replace and New calls are concentrated where performance genuinely requires fresh material. That’s the point of pathways: they make the high-leverage moves visible first.
How does assigning pathways change a project’s direction?
Pathways change direction because the largest carbon categories are usually the ones easiest to retain. As operational energy decarbonises, embodied carbon makes up a growing share of whole-life carbon (World Green Building Council, “Bringing Embodied Carbon Upfront”, 2019), and structure is typically the dominant embodied-carbon category. Settle structure as Retain and you’ve moved the biggest lever first.
The cost story tends to reinforce the carbon story rather than fight it. Across Retain, Reuse, and Refinish, the indicative cost deltas are negative: you’re spending less because you’re buying and building less. Replace and New are where cost rises, so concentrating them only where performance demands keeps both columns in check.
This is also why reuse versus new build is rarely an all-or-nothing question. Real projects are a mix of pathways, and the mix is the strategy. A small shift, moving a category from Replace to Reuse, can change a project’s carbon and cost trajectory measurably.
Pathways won’t certify anything. What they do is make the trade-offs explicit early, so the conversation between designer, developer, and consultant starts from structured ground rather than gut feel.
FAQ
Are these carbon factors certified or compliance-grade?
No. The factors (Retain 0.05 to New 1.00) are indicative defaults for early comparison and decision support. They are not certified figures and must not be used for compliance, certification, or official reporting. For formal results, commission a qualified whole-life carbon assessment; pathways orient the strategy that precedes it.
What’s the difference between Reuse and Refinish?
Reuse relocates or repurposes a whole element with minimal processing (carbon factor 0.15). Refinish keeps the element in place but renews its surface, by re-coating, re-sanding, or restoring (carbon factor 0.40). Reuse carries less added carbon because little new material is involved; Refinish adds finishes to an existing substrate.
Do the cost deltas include labour and demolition?
The indicative cost deltas are rough ranges versus building an element new, oriented using ÖNORM B 2061 cost structures. They reflect that demolition and labour can push Replace toward or above baseline (±0% to +15%), while retention-led pathways usually cost less. Treat them as direction, not a quote.
Can one project use several pathways at once?
Yes, and most do. You assign a pathway per element, so a single refurbishment routinely mixes Retain for structure, Refinish for finishes, and New where performance requires it. The combination, the pathway mix, is the project’s circularity strategy.
Where this leaves you
Circularity pathways turn a vague intention (“keep what we can”) into an element-by-element decision with a clear carbon and cost direction. The factors are indicative, the framing is comparative, and the value is in making the high-leverage moves, usually retaining structure, visible before anything is locked in.
Elementa is built for exactly that moment: classify each element, compare pathways, and see indicative impact and cost ranges before formal assessment. If that’s useful to how you work, join the waitlist to be among the first to try it.