Cradle‑to‑Site (C2S)

The Cradle-to-Site (C2S) scope covers all the environmental impacts generated from raw material extraction (the cradle) to the moment a product or building system arrives at the construction site, before it is installed. It is a partial life cycle boundary used mainly in construction to quantify the embodied carbon and other impacts that occur upstream of a building entering service.

Within the European framework for the sustainability of construction works (standard EN 15804, which governs Environmental Product Declarations for construction products), the life cycle is divided into modules. Cradle-to-Site typically corresponds to:

• Production (modules A1-A3): raw material extraction, transport to the manufacturer and manufacturing.
• Transport to site (module A4): road, maritime or rail logistics from the factory gate to the site.
• On-site construction-installation (module A5): energy, water and waste associated with installation, where this stage is included.

The use phase (modules B1-B7) and the end-of-life stage (modules C1-C4) are excluded. By stopping at the site boundary, C2S lets architects, engineers and developers assess the impact of their material choices and logistics before the building is in operation.

Why it matters for low-carbon construction

Embodied carbon, the emissions locked into materials and construction, can represent a large share of a building's whole-life carbon, particularly for new, energy-efficient buildings where operational emissions are already low. Measuring impacts up to the site helps to:

• Compare materials and suppliers on a consistent basis (for example, conventional cement versus lower-clinker blends).
• Optimise logistics, since transport (module A4) can be a significant contributor for heavy or distant materials.
• Support public procurement and green building certifications that increasingly request embodied carbon data.

Cradle-to-Site sits within the broader concept of whole-life carbon and is closely related to embodied carbon.

How it is calculated

1. Define the functional unit (for example, one square metre of floor area, or one tonne of a given material).
2. Collect production data (A1-A3), ideally from verified Environmental Product Declarations or recognised life cycle inventory databases.
3. Model transport to site (A4) using real distances and transport modes.
4. Where relevant, quantify on-site installation processes (A5): energy use, packaging and installation waste.
5. Aggregate the global warming potential, expressed in kg CO2 equivalent, applying characterisation factors consistent with the IPCC assessment reports.
6. Document assumptions and, where possible, obtain an independent critical review for transparency.

This approach follows the logic of a Life Cycle Assessment (LCA) applied to a defined boundary, governed for construction products by the EN 15804 rules.

Strategies to reduce Cradle-to-Site impacts

• Lower-carbon materials: cements with supplementary cementitious materials, steel with high recycled content, or timber and bio-based products.
• Optimised design: lighter sections and prefabrication to reduce material use and on-site cutting and waste.
• Sustainable logistics: shorter supply chains, rail or maritime transport for bulk materials and cleaner vehicles for the last mile.
• Efficient site management: electrified equipment where feasible and recovery of packaging and installation waste.

Relationship with other life cycle scopes

• Cradle-to-Gate: covers modules A1-A3 only (up to the factory gate); useful for comparing products independently of where they are used.
• Cradle-to-Practical Completion: extends the boundary to the point at which the building is handed over.
• Cradle-to-Grave: adds the use phase and end-of-life for a full life cycle view.

Tools that combine building information modelling with LCA databases, together with Environmental Product Declarations from manufacturers, make it increasingly practical to calculate Cradle-to-Site impacts during design. Initiatives such as the Digital Product Passport are expected to improve access to verified product data along the supply chain.

Measuring impacts up to the construction site is becoming a key step in reducing embodied carbon before buildings enter service. At Manglai we help companies measure their carbon footprint and prepare their sustainability reporting. Discover how Manglai can help you.