Whole life carbon reporting and when it is required

A whole life carbon assessment measures the greenhouse gas emissions of a building across its whole life: the materials, the construction, the energy used in operation, the maintenance and replacement over time, and the end of life. There is no national planning requirement for one in England. The whole life carbon assessment requirement comes from local policy, most prominently in London, where applications referable to the Mayor have to report whole life-cycle carbon using the Greater London Authority's guidance and template.

So the first question for an architect is not how to model it. It is whether the authority you are applying to asks for it, and in what format.

What the assessment measures

A Whole Life Carbon Assessment reports emissions in kilograms of carbon dioxide equivalent, normally normalised per square metre of gross internal area. It covers the embodied carbon in products and construction, the operational carbon from regulated and unregulated energy, the recurring emissions from replacing components, and the emissions and credits arising at demolition.

Embodied carbon is the part that planning policy has moved towards, because operational carbon is already governed by the Building Regulations. A modern, well insulated building can carry more embodied carbon than it will ever emit in operation, which is why the retention question comes first.

The output is a number, a set of modules, and a narrative explaining the decisions that produced them. The narrative is what officers read.

The methodology and edition to use

Use the RICS professional standard on whole life carbon assessment for the built environment, second edition, which replaced the 2017 first edition and applies to assessments from mid 2024. It sets the scope, the calculation rules, the data quality requirements and the reporting format, and it aligns with the European standard for sustainability assessment of construction works.

Two practical rules. State the edition and the version of any supporting tool in the assessment, because comparisons between assessments on different editions are not valid. And state the data sources for the main material quantities, distinguishing between generic datasets, industry average figures and product specific environmental declarations, because an officer or a reviewer will test the biggest contributors.

Life cycle modules and what must be reported

The modules follow the standard life cycle stages:

Report module D separately rather than netting it off the total. That is the single most common error, because a large module D credit can make a concrete frame look better than it is, and reviewers will ask for the figures without it.

The practical reporting split most authorities want is upfront carbon (A1 to A5), the life cycle total excluding operational energy, and the total including it, with module D stated alongside.

Which authorities require it and at what scale

In London, whole life-cycle carbon reporting applies to applications referable to the Mayor, with the GLA's own guidance setting the method and a reporting template that has to be submitted at planning stage and again after construction. Borough policies sometimes extend the requirement to smaller schemes, and a growing number of authorities outside London ask for an assessment through local plan policy or a validation list entry.

Check three documents for your site before scoping the work:

1. The adopted local plan policy on carbon and sustainable design
2. The authority's local validation list, which is where the requirement is usually enforced
3. Any supplementary planning document on sustainable design or energy

Proposals to bring embodied carbon reporting into the Building Regulations have been promoted by industry for several years but have not been made law, so treat any claim that it is a national requirement with caution and verify the current position before advising a client. The PlanScope planning law timeline is a place to follow changes of this kind, and emerging local policy carries different weight at different stages, as plan making reform and what happens to emerging plans explains.

Benchmarks and how they are used

Benchmarks exist for common building types, expressed per square metre, and the GLA guidance publishes both a benchmark and a more demanding aspirational figure for several typologies. Industry bodies publish their own targets, with design targets set against dates rather than against current practice.

Use them carefully. A benchmark comparison is only meaningful where the scope, the modules reported and the floor area definition match, and the differences between published sets are large enough to flip a conclusion. State which benchmark you are comparing against, and which modules it covers.

Where the scheme exceeds the benchmark, say so and explain the reason. A tall building with a deep basement and a long span structure will exceed a mid-rise benchmark, and a frank explanation reads better than a comparison quietly omitted.

Retention and retrofit as the first option

Policy in London requires the retention of existing buildings to be considered before demolition, supported by evidence rather than assertion. In practice that means a comparison: the whole life carbon of refurbishing and extending the existing structure against the whole life carbon of demolition and rebuild, on a like for like basis of floor area and performance.

The comparison has to deal fairly with what retention can deliver. Where the existing frame cannot take the load, the floor to ceiling heights do not work, or the building cannot reach the required performance without rebuilding the facade, say so with evidence from a structural appraisal.

Alongside this, a Circular Economy Statement deals with material reuse, design for disassembly and construction waste, and the two documents should use the same material quantities. Different quantities in the two submissions is a straightforward way to lose a reviewer's confidence.

Submitting the assessment in the required format

Where a template exists, use it. The GLA's spreadsheet template carries the module breakdown, the material quantities and the benchmark comparison in a fixed structure, and a bespoke report submitted instead of the template usually comes back.

Include in the submission:

• The completed template or equivalent structured data
• A narrative report explaining the modelling choices and the biggest contributors
• The data sources for the main quantities, with any product specific declarations referenced
• The retention and demolition comparison where that policy applies
• The reduction measures adopted, with the carbon saving attributed to each
• A statement of who prepared the assessment and their competence

The last point matters because councils expect a suitably qualified author for this type of work and professional review is strongly advised. PlanScope drafts the narrative and the structure of the assessment from a postcode and a short set of answers, flags the quantities it does not hold rather than inventing them, and you can send the draft out for review before submission. For specialist technical reports, qualified professional input may be required.

Start by reading your authority's validation list, then scope the modelling to what it asks for.

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.