Sector PCF — Construction Materials Calculator | EN 15804 & ISO 14067 Embodied Carbon

What a Construction-Materials PCF Is, and Why the Material Layer Dominates

A product carbon footprint is the greenhouse-gas total attributable to a defined quantity of a product across a stated set of life-cycle stages. For construction materials the product-level standard is ISO 14067, and the construction-specific accounting rules that make EPDs comparable come from EN 15804 — the European core product category rules, whose international parent is ISO 21930. A material’s PCF is reported per its declared unit: a cubic metre of concrete, a kilogram of steel, a square metre of glazing. The declared unit is part of the number — 196 kg CO₂e means nothing until you know it is per cubic metre.

The reason this matters more each year is structural. As operational energy decarbonises through grid greening and efficiency, the share of a building’s whole-life carbon that is fixed at the point of manufacture — the embodied, or upfront, carbon — rises correspondingly. A material PCF is the atom of that accounting: get the per-unit figures and their boundaries right, and the building-level total computed under EN 15978 follows.

Cradle-to-Gate Is the Default — and the Most Misread Boundary

Module A1–A3 covers raw material supply (A1), transport to the factory (A2) and manufacturing (A3): everything up to the factory gate. It is the universal, always-declared boundary — every EPD publishes it — which is exactly why it is the default here and the figure most often quoted without its qualifier. Cradle-to-gate is not cradle-to-grave: it excludes getting the material to site, installing it, its decades in service, and its eventual demolition. Comparing one supplier’s cradle-to-gate figure against another’s cradle-to-grave figure is the single most common non-comparability error in embodied-carbon work.

Operational Control Is Not the Question Here — the Declared Unit Is

Unlike a Scope 1/2/3 inventory, a material PCF does not turn on who owns or operates anything. It turns on the declared unit and the module set. Two EPDs for nominally the same product are only comparable if they share a declared unit and declare the same modules. This calculator enforces both: it shows each product’s native unit as the input suffix and lists, in the audit trail, precisely which modules were summed.

Included vs Excluded

EN 15804 Modules — What A1–A3, C3/C4 and D Each Capture

EN 15804 divides a product’s life cycle into modules labelled by stage. This calculator works with four of them — the three the boundary toggle exposes plus the always-separate recovery credit. The remaining modules (A4, A5, the B-series use stage) are modelled at building level, not product level, and are out of scope here.

The Standards Stack — ISO 14067, EN 15804, EN 15978, ICE, ÖKOBAUDAT

Five reference frameworks sit behind a construction-materials PCF, each answering a different question.

• ISO 14067 — the product-level carbon-footprint quantification standard. Defines what a PCF is and how it is calculated, built on the ISO 14040/14044 life-cycle-assessment framework.
• EN 15804 (parent: ISO 21930) — the construction-product core category rules. This is what makes one manufacturer’s EPD comparable with another’s: same modules, same declared-unit logic, same indicators. The factors in this calculator are EN 15804+A2 values.
• EN 15978 — assembles product EPDs into a whole-building life-cycle assessment. The product PCF is the input; EN 15978 is the building-level total.
• ICE database — the Inventory of Carbon and Energy, a widely used open embodied-carbon dataset; useful as a cross-check against EPD figures.
• ÖKOBAUDAT — the German federal construction-LCA database that supplies most of this calculator’s EPD-derived rows (steel, masonry, glass, insulation, timber, ready-mix concrete).

EPD-Derived vs Database-Average — and Why the Gap Matters

A product-specific EPD reflects one manufacturer’s actual process; a database-average row reflects a market or technology mean. The calculator uses market-average EPD-derived rows so that a figure is available for every product, but where a supplier-specific EPD exists it will almost always differ — often materially. Treat the calculator’s figure as a defensible default for screening and early design, and substitute supplier EPD data once you have it, recording the source against each line.

Headline Embodied-Carbon Factors by Material

The figures below are the cradle-to-gate Module A1–A3 values the calculator reads from MasterBrain v2026.11, on an AR5 GWP-100 / EN 15804+A2 basis. Read the unit column on every row — declared units differ within a family, and two rows that look comparable may be per-kg against per-m³.

Concrete and Cement

Ready-mix concrete is declared per cubic metre; the C-grade is the compressive-strength class. The calculator’s reference grade and worked-example default is C30/37. Cement and supplementary cementitious materials (SCMs) are declared per kilogram — they are constituents, quoted here for the substitution discussion in the next section, not for adding to a ready-mix figure.

GGBS and fly ash carry a second value under by-product (zero-burden) allocation — covered in the next section. Calcined clay’s lower bound of 0.048 kg CO₂e/kg is an EPD-specific uncertainty floor (an efficient flash-calcined product), not an allocation alternative. Available ready-mix grades run C8/10 through C55/67; C32/40 and C40/50 are not in the dataset.

Steel

Steel is declared per kilogram and described by product, not by steelmaking route — these are single market-average EPD rows, so there is no separate blast-furnace (BOF) versus electric-arc (EAF) figure to compare within this dataset.

Aluminium

Aluminium is the one metal in this set with a virgin/recycled pair, so it is also the one where the recycled-content control does anything. The contrast is roughly thirty-nine-fold — primary ingot against recycled secondary.

The primary-ingot default of 10.1 is the import-weighted EU consumption mix — the honest default for unknown-origin metal; an EU-produced alternative of 6.6 applies where origin is documented. The extruded-profile figure is the ingot value plus 0.38 conversion. Aluminium carries no Module D row in this release: its recycling benefit is expressed entirely through the A1–A3 figure via recycled content, and under the + Module D boundary aluminium simply shows an em-dash.

Timber and Bio-Based Materials

Timber A1–A3 figures are net-negative because ÖKOBAUDAT’s total-GWP indicator nets the biogenic carbon taken up as the tree grew. This stored carbon is a memo item, not a free offset — see the Module D and biogenic discussion below.

Masonry, Glass and Insulation

Watch the units in this group. Most bricks and blocks are per cubic metre, but sand-lime brick is per kilogram. Stone wool is per cubic metre, but glass wool is per kilogram. Glass and plasterboard are per square metre. Side by side, the magnitudes look wrong until you read the unit.

Allocation, Recycled Content and Module D — Where PCFs Diverge

Two materials can have the same physical process and still carry different PCFs because of three accounting choices: how shared burdens are allocated, how recycled content is credited, and whether end-of-life benefits are netted or reported separately. These are where most legitimate disagreements between PCFs actually live.

Economic vs By-Product Allocation — the SCM Lever

GGBS and fly ash are co-products of iron-making and coal combustion. How much of the parent process’s carbon they should carry depends on the allocation method. Under economic allocation (the MPA default), they carry a share proportional to their market value. Under by-product (zero-burden) allocation, they enter the concrete carrying almost nothing, on the basis that they would have been produced regardless. The calculator’s global allocation toggle switches between the two — and it moves only the rows that carry a by-product alternative (the SCMs), nothing else.

The choice is not cosmetic: at scale it can move a concrete mix’s binder carbon substantially. Whichever you use, disclose it — an auditor will ask which allocation method backs every SCM line.

Recycled Content — Effectively Aluminium-Only Here

The recycled-% control changes a result only where MasterBrain carries a virgin/recycled pair. For this construction set that is aluminium (ingot 10.1 against recycled secondary 0.26) plus membrane plastics. Steel, concrete, cement, masonry, timber and insulation have no recycled MasterBrain pair, so the control is disabled for them — there is no recycled-steel or recycled-concrete blend in this tool. The concrete-side lever is the SCM allocation toggle, not a recycled blend.

Module D and Biogenic Carbon — Always Separate

Module D captures benefits beyond the system boundary: the credit for material that is reused, recovered or recycled at end-of-life. EN 15804 is strict that Module D is reported on its own line and never netted into the A1–A3 or A-to-C totals — the same integrity principle that keeps carbon removals off gross emissions in land-sector accounting. A material that recovers well at end-of-life has two facts, not one nettable number.

For timber the biogenic story is specific. The A1–A3 figure is already net-negative because total-GWP nets the carbon the tree absorbed (softwood −629.4 kg CO₂e/m³). The calculator surfaces the stored biogenic carbon as a separate disclosure memo and does not re-net it; under the + End-of-life boundary, the release of that stored carbon appears in Modules C3/C4. So the sequence is: biogenic uptake already inside A1–A3, a separate memo of how much carbon is stored, and its release booked at end-of-life — not a free-floating offset.

Worked Example — PCF of One Cubic Metre of Concrete, Three Boundaries

This traces the calculator’s default product — C30/37 ready-mix — through all three boundary settings, reconciling to what the engine displays. Figures use the engine’s magnitude-aware rounding (no fixed decimal places).

Three things to read from this. First, C4 is not published for concrete, so the + End-of-life total adds only C3 — the engine shows an em-dash for C4, not a zero, and the audit trail records that C4 was absent rather than nil. Second, the headline under + End-of-life is 201, the sum of the modules that exist. Third, the Module D credit of −12.1 sits on its own line and never reduces the 201 — a reader who wants the recovery benefit sees it, but it is not folded into the reported footprint. For a portfolio of several products, the engine repeats this per line and reports both per-declared-unit figures and a summed portfolio total.

Where the Reductions Actually Are

The largest, cleanest embodied-carbon reductions in this dataset are not spread evenly — they cluster in a few material choices. The chart compares headline A1–A3 figures, normalised to make the cross-material magnitudes legible (note that the underlying declared units differ — this is a directional comparison, not an additive one).

Per-kg products only; AR5-100, EN 15804+A2 A1–A3. Bars scaled to the per-kg maximum for legibility — do not read across to per-m³ or per-m² products.

The Two Levers That Move Most

For the metals in scope, the dominant lever is recycled content in aluminium — the drop from primary ingot to recycled secondary is roughly thirty-nine-fold, by far the steepest reduction in the dataset. For concrete, the lever is binder: replacing clinker with SCMs, and the allocation method that backs them. Compare specific choices side by side with the Material Substitution Savings Calculator, and for individual material families in depth see the embodied-carbon concrete & cement and steel & aluminium calculators.

CBAM and the Regulatory Pull on Embodied Carbon

The EU’s Carbon Border Adjustment Mechanism (CBAM) puts a price on the embedded emissions of imported steel, aluminium, cement and other carbon-intensive goods — turning embodied carbon from a voluntary disclosure into a border cost. That regulatory pull is why per-material carbon figures now matter to procurement, not just to sustainability teams.

The practical consequence: a cradle-to-gate PCF from this tool is the right figure for design decisions and EPD-based disclosure, while CBAM defaults govern the import-cost calculation. They inform each other but never share a total.

Audit Checklist — Common Construction-PCF Reporting Errors

The errors below are the recurring ones in EPD-based embodied-carbon reporting — the ones that produce non-comparable numbers or qualified verification opinions.

Data Sources, Factor Provenance and Uncertainty

All factors are read from MasterBrain v2026.11 and trace to three published sources, each on an AR5 GWP-100 / EN 15804+A2 basis:

• ÖKOBAUDAT 2024 — the German federal construction-LCA/EPD database; supplies the steel, aluminium-adjacent, masonry, glass, insulation, plasterboard, timber and ready-mix concrete rows.
• MPA Cement Fact Sheet 18 (Rev 4, 2025) — the Mineral Products Association’s UK cement and SCM dataset; supplies CEM I Portland and the supplementary cementitious materials (GGBS, fly ash, calcined clay, limestone fines), including the economic and by-product allocation values.
• European Aluminium Environmental Profile Report 2024 (V2.0) — supplies the primary, recycled and extruded aluminium rows, including the EU consumption-mix and EU-produced alternatives.

Uncertainty and Data Quality

EPD-derived market averages carry the variability of the underlying product population; supplier-specific EPDs are tighter but available only where a manufacturer has published one. The calcined-clay row, for instance, spans from a 0.274 market value down to a 0.048 EPD-specific floor for an efficient flash-calcined product — a span wide enough that the design choice of which calcined clay matters as much as the decision to use it. Where a figure drives a material decision or a disclosure, seek the supplier EPD and substitute it, recording the registration number against the line.

Module Coverage

Coverage is intentionally ragged and reported faithfully: concrete, tile and plastics carry no C4; cement rows are A1–A3 only; paint has no C3; aluminium and cement carry no Module D. The calculator reads each module live, sums only what exists, shows an em-dash for what doesn’t, and lists the summed set in the audit trail. This is by design — zero-filling absent modules would fabricate precision the EPDs do not support.

Frequently Asked Questions

Methodology Notes and Limitations

AR5-100 / EN 15804+A2 basis throughout. Every factor the calculator reads is AR5 GWP-100, the EPD convention. The page is internally consistent, but its figures are not directly interchangeable with AR6-100 corporate-inventory factors without restating the basis.

Boundary is A1–A3 → +C3/C4 → +D, not gate-to-grave. Transport to site (A4), installation (A5) and the use stage (B1–B7) are out of scope and belong to the EN 15978 whole-building workflow.

Market-average EPD rows. Factors are EPD-derived market averages so a figure exists for every product; supplier-specific EPDs will differ and should be substituted where available, with the source recorded per line.

Module coverage is reported faithfully, never zero-filled. Absent modules show an em-dash and are excluded from sums; the audit trail lists which modules were summed for each line.

Recycled-content blending is aluminium-and-membranes only. Other families have no virgin/recycled pair in the dataset; the control is disabled for them.

Concrete mix build-up is deferred. v1 selects finished products only. Composing a mix from binder, SCM and aggregate constituents (including LC3 by clinker-factor blending) is scheduled for v1.1; until then, LC3 is design context quoted from its constituent rows, not a calculator preset.

Where the per-material method lives. This calculator works across material families; the full boundary, allocation rules and dataset provenance for each are documented separately — concrete and cement, steel and aluminium, timber and bio-based materials, masonry and finishes, plastics and membranes, and the building envelope. The whole-building workflow these A1–A3 figures feed into is EN 15978.