Whole life carbon assessment: reporting structure

A whole life carbon report structure that an officer can actually check has six parts. Scope and boundaries, results by module, data quality, benchmark comparison, the reduction measures tested, and what is being committed to through conditions or obligations. Get those in the right order and the assessment reads as evidence. Get them wrong and it reads as a spreadsheet with a cover page.

The reference point is the RICS professional standard on whole life carbon assessment for the built environment, second edition, which sets the methodology most English authorities now expect. Where a scheme is referable in London, the Greater London Authority's own guidance and template sit on top of it.

Scope, boundaries and the study period

Open with the things a reviewer needs before any number makes sense. The assessment boundary, the reference study period, the floor area basis and the version of the methodology used.

State each plainly:

1. The buildings, structures and external works included, and anything excluded with the reason
2. The reference study period, conventionally 60 years, stated as an assumption rather than assumed silently
3. Gross internal area in m2, with the source drawing and revision
4. The methodology and edition, and the calculation tool used
5. The date of the assessment and the design stage it reflects

Design stage matters more than people credit. A concept-stage assessment based on area schedules and generic data cannot be compared with a technical-design assessment built from a bill of quantities, and reviewers who see the stage stated stop asking why the numbers moved.

Modules A to C, and why module D sits apart

Report by module, using the standard structure. A1 to A3 for product, A4 and A5 for construction including demolition and construction waste, B1 to B7 for the use stage including replacement and operational energy, and C1 to C4 for end of life.

The headline figure is the total of modules A to C, expressed in kgCO2e per m2 of gross internal area. Module D, which covers benefits and loads beyond the system boundary such as the recovery potential of materials at end of life, is reported separately and never netted off the headline. That single discipline is the most common error in submitted assessments, and reviewers look for it first.

Report embodied carbon and operational carbon separately as well as together. A scheme with low embodied carbon and a heavy operational load tells a different story from the reverse, and a single combined figure hides the trade-off that the design team actually made. The Energy Statement should be consistent with the operational figures used here, and inconsistency between the two documents is a routine reason for further information requests.

Data sources and how to state quality

Set out a data hierarchy and then show where each element sits within it. Product-specific environmental product declarations at the top, sector or generic declarations next, then recognised database figures, then assumptions.

A short table works better than prose here. One row per element, with the quantity source, the carbon factor source, and a quality rating. Substructure, superstructure, facade, internal finishes, services, external works.

Be honest about the weak rows. An assessment that marks its services data as generic and explains why is more credible than one that presents every figure with the same confidence. And where an assumption is doing heavy lifting, such as a replacement cycle for a facade system, state the assumption and test it in the sensitivity analysis.

Benchmarks and how to present against them

Comparison only means something when like is compared with like. State the benchmark source, the building type it covers, the modules it includes and the study period it assumes, then place the scheme against it.

Three habits make the comparison legible. Use benchmarks that include the same modules as your headline figure rather than adjusting a published figure silently. Show the scheme against both a business-as-usual reference and an aspirational target where both exist. And present the figure per m2 alongside the absolute total, because a large building can look efficient per square metre while adding a great deal of carbon.

Where a local policy sets a target, quote the policy and the target in the same sentence as the result. Officers are checking compliance with a policy, not admiring an analysis.

Reduction measures and the options tested

This is the section that distinguishes an assessment from a calculation. Describe the options considered, what each would have saved, and why the design landed where it did.

Cover the structural options first, because that is where the largest savings sit. Retention or partial retention of an existing structure, grid and span rationalisation, concrete mix design and cement replacement, steel with recycled content, timber where fire strategy allows, and reduced basement extent. Then the facade, the finishes specification, and the services replacement strategy.

Quantify each one. A measure described as considered, with no number attached, reads as a list rather than as work done. Where an option was rejected on cost, buildability or fire strategy grounds, say which, because a reviewer who can see the reasoning is far less likely to ask for the option to be revisited.

Reuse and material recovery link directly to the Circular Economy Statement where one is required, and the two documents should share the same demolition and material quantities.

Reporting format, units and the summary table

Lead with a one-page summary. Total kgCO2e for modules A to C, the same figure per m2 GIA, embodied and operational split, module D reported separately, the benchmark comparison, and the percentage reduction achieved against the baseline option.

Use kgCO2e throughout and state whether figures are rounded. Give the module breakdown as a table, and the elemental breakdown as a second table. Append the calculation model rather than summarising it, because reviewers increasingly ask for the underlying file and refusing to supply it costs a determination cycle.

A Whole Life Carbon Assessment submitted in a proprietary format nobody can open is functionally a missing document. Export to something ordinary.

Securing commitments through conditions

The assessment describes intentions. Conditions and obligations are what makes them binding, and the assessment should say which mechanism is proposed for each commitment.

Expect a condition requiring the approved reduction measures to be implemented, a condition or obligation requiring a post-construction assessment based on as-built quantities, and in London a requirement to report the as-built figures to the authority. Draft the wording you can live with and offer it, rather than waiting for wording you cannot.

One honest uncertainty. Benchmarks and policy targets are moving, and a figure that is acceptable under a current local policy may be measured against a tighter one by the time a reserved matters application is determined. Say in the report which policy version the assessment responds to, and date it.

PlanScope drafts documents of this kind from your project details, structured to UK planning policy, with facts it cannot verify flagged rather than invented. Carbon modelling and the professional judgement behind it stay with your assessor. Browse all 66 report types to see how the sustainability documents fit together.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.