Why it matters now
From 2026 the EU CSRD (Corporate Sustainability Reporting Directive) and EU Taxonomy force contractors and developers to report embodied carbon (A1–A5 life-cycle modules), not just operational energy. Estimators need carbon numbers next to price numbers at the BOQ line level.
Method
Carbon = quantity × carbon factor, applied per material resource line — exactly parallel to quantity × unit price = cost.
work item → components[] → material lines → quantity × EF (kg CO₂e / unit) → line carbon
BOQ roll-up: Σ line carbon = project embodied carbon (A1–A3) + transport/waste (A4–A5)
Data sources for factors
| Source | Coverage | License |
|---|---|---|
| ÖKOBAUDAT (DE) | building materials | open |
| INIES (FR) FDES | products | open |
| ICE Database (UK) | embodied carbon | free registration |
| EPD libraries (ECO Platform) | manufacturer EPDs | varies |
The CWICR bases already carry per-resource quantity and unit — attach an EF (kg CO₂e/unit) column for the materials and the roll-up is automatic.
What to compute per project
- A1–A3 embodied carbon per BOQ section and per trade (from material lines).
- A4–A5 transport + site waste assumptions (distance bands, waste rates per material).
- kg CO₂e / m² and / m³ intensity benchmarks for early design.
- Hotspot report: top 10 carbon lines (usually concrete, steel, aluminium, insulation).
EU Taxonomy / CSRD alignment
- Map each work item to the taxonomy activity (construction of new buildings 7.1, renovation 7.2, …).
- Report DNSH (Do No Significant Harm) screening: circularity, waste, water for the top materials.
- Keep the evidence trail: factor source + version per line (auditors ask).
Honest limits
- Carbon factors are regional and versioned — never mix databases without noting it.
- BIM takeoff gives geometry; carbon needs material takeoff (from CWICR
resource_name+resource_quantity). - Early-phase estimates are ±30–50%; label them as such.