Cradle‑to‑Site (C2S)

The Cradle-to-Site (C2S) scope covers all emissions and environmental impacts generated from raw material extraction (cradle) to the arrival of the product or construction system at the building site.

It includes:

• Production (modules A1–A3 of EN 15804): extraction, processing, and manufacturing.
• Transport to site (A4): road, maritime, or rail logistics.
• On-site activities (A5): energy, water, and waste resulting from installation.

The use phase (B1–B7) and end-of-life (C1–C4) are excluded. C2S enables architects, engineers, and developers to assess embodied carbon and other impacts before the building enters operation.

Climate and regulatory relevance

• Nordic regulations (Sweden, Norway, Denmark) set limits in kg CO₂e/m² for 2025–2030 based on C2S.
• EU Green Taxonomy requires < 450 kg CO₂e C2S/m² for office buildings.
• Public procurement: The Netherlands assigns a 20% weighting to C2S carbon in road and bridge tenders.

Detailed methodology

1. Define the functional unit (e.g., 1 m² of internal floor area over 60 years).
2. Collect A1–A3 data: verified EPDs, ecoinvent v3.9 or ICE v3 databases.
3. Model transport (A4): real distances and modes (HBEFA, ecoinvent).
4. Quantify site processes (A5): crane fuel, material cutting, packaging.
5. Sum GWP100 (IPCC AR6) and other indicators: AWARE, ADP, ODP.
6. Verification: critical review by an LCA expert, consistency with EN 15804+A2 PCR.

Key indicators

• C2S GWP: kg CO₂e/m² GFA.
• A5 waste mass: kg/m².
• Water footprint A2–A5: m³ eq AWARE.
• Embodied carbon factor: % of total C2G occurring in A1–A5.

Reduction strategies

• Low-carbon materials: LC3 concrete, H-DRI steel with 80% scrap.
• Optimised design: lighter sections, 3D prefabrication to minimise on-site cutting.
• Sustainable logistics: B100 biofuels, rail or bulk maritime transport.
• Net-zero construction site: electric cranes, HVO generators, on-site packaging recycling.
• LEAN planning: Just-in-Time delivery to reduce storage and internal handling.

Case study: Passivhaus housing in Navarra (2024)

• Baseline design: prefabricated concrete structure (520 kg CO₂e/m² C2S).
• Interventions:
  • Replace 50% of clinker with fly ash.
  • Rail transport from quarry (–140 km) and electric truck for last mile.
  • “Dry-joint” assembly without fresh concrete pours.
• Result: C2S reduced to 330 kg CO₂e/m² (–37%), +3% CAPEX; ROI via green marketing and 7% above-market sales price.

Links to other scopes

• Cradle-to-Gate: excludes A4–A5; useful for supplier comparisons.
• Cradle-to-Practical Completion: C2S + fixed equipment (B8) such as HVAC.
• Cradle-to-Grave: adds use and end-of-life for a full lifecycle view.

Monitoring and tools

• BIM + LCA plug-ins: One Click LCA, Tally, eTool.
• Construction digital twins: capture fuel use and waste in real time.
• EPD APIs: automated access to verified A1–A3 data.
• Government calculators: Klimatkalkyl (Sweden), OneClick SE.

Challenges and trends 2025–2030

• Hourly dynamic LCA: reflecting variable renewable energy during construction.
• Digital Product Passport: integrating C2S data for supply-chain transparency.
• Green EPC contracts: bonuses for ≥10% C2S reduction vs baseline.
• Logistics blockchain: traceability of routes and emissions in A4.

The Cradle-to-Site scope is becoming the key metric for reducing embodied carbon in construction before buildings enter service. Adopting low-carbon materials, sustainable logistics, and net-zero construction sites can cut up to 40% of pre-operational emissions, ensuring regulatory compliance and improving competitiveness in the green real estate market.