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When Do You Need a Whole Life Carbon Assessment?

Jul 2, 2026 • 6 min read • By visionredesign

Whole Life Carbon Assessments (WLCAs) are appearing on more planning applications than they were even a few years ago. If you’re an architect or planning consultant, you’ve probably seen them requested by local authorities, discussed during design team meetings or included as part of a client’s sustainability brief.

One of the most common questions we get asked is whether a WLCA is actually required.

The honest answer is that there isn’t a simple yes or no.

Unlike SAP calculations or overheating assessments, there isn’t currently a national planning requirement that says every development must include a Whole Life Carbon Assessment. Instead, requirements are largely driven by local planning policy, client aspirations and sustainability frameworks such as BREEAM.

If you’re new to Whole Life Carbon, we’ve already covered the fundamentals in our article Why Whole Life Carbon Assessments Are Becoming Central to UK Development, including the different lifecycle stages and why embodied carbon is becoming an increasingly important part of sustainable design.

This article focuses on the practical questions we hear most often—when a WLCA is likely to be needed, how it fits into planning and BREEAM, and why timing is often more important than people realise.

Is a Whole Life Carbon Assessment a planning requirement?

At the time of writing, there is no national planning policy that requires every development in England to submit a Whole Life Carbon Assessment.

That doesn’t mean they’re uncommon.

The best-known example is London, where the Greater London Authority requires Whole Life Carbon Assessments for referable developments under the London Plan. Alongside this, a number of local authorities are introducing policies that encourage or require applicants to demonstrate how embodied carbon has been considered as part of the design process.

Outside London, the picture is more varied. Some councils have adopted local planning policies relating to embodied carbon, while others may request additional information as part of a wider sustainability statement.

For planning consultants, it’s worth checking local validation requirements at the beginning of a project rather than assuming the same approach applies everywhere. We’ve seen projects where a WLCA wasn’t initially considered, only for it to become a planning requirement later in the programme, creating unnecessary time pressure.

Reference: Greater London Authority Whole Life-Cycle Carbon Guidance

Planning isn’t the only reason to carry out a WLCA

It’s easy to think of a Whole Life Carbon Assessment as another planning document, but that’s often missing the bigger picture.

The real value comes from using the assessment to inform design decisions while there is still flexibility.

For example, changing a structural frame from steel to timber, retaining more of an existing building or selecting lower-carbon materials can significantly affect embodied carbon. Those decisions are much easier to make during concept and developed design than once the technical design has been completed.

We’ve been involved in projects where the assessment was only commissioned because it appeared on a planning validation checklist. By that point the structural design had already been agreed and the opportunity to make meaningful reductions in embodied carbon had largely passed.

A WLCA is most valuable when it’s treated as a design tool rather than a compliance exercise.

How does a Whole Life Carbon Assessment support BREEAM?

Whole Life Carbon is also becoming more relevant on projects targeting BREEAM certification.

While BREEAM doesn’t simply award credits for producing a WLCA, assessing life cycle impacts during the design process supports informed decision making and contributes towards a more robust sustainability strategy.

For architects, this often leads to useful discussions around:

Like most sustainability assessments, the earlier these conversations happen, the more influence they can have on the final outcome.

If your project is targeting BREEAM, it’s generally far easier to integrate Whole Life Carbon thinking during RIBA Stages 2 and 3 than to revisit major design decisions later.

Chat to us about your BREEAM requirements

When should a WLCA be carried out?

This is probably the question that makes the biggest difference to the usefulness of the assessment.

A common misconception is that a Whole Life Carbon Assessment should only be produced once the design has been finalised.

In reality, the opposite is often true.

An early-stage assessment inevitably relies on assumptions, but those assumptions allow different design options to be compared before significant decisions have been made.

As the project develops, the assessment can then be updated with more detailed information.

A simple way of thinking about it is:

RIBA Stage 2 – Concept Design

Compare structural systems, building form and high-level material choices.

RIBA Stage 3 – Spatial Coordination

Refine specifications and support planning submissions where required.

RIBA Stage 4 – Technical Design

Update calculations using developed design information.

Construction and completion

Produce final reporting where required for planning, certification or client requirements.

Rather than being a single report, a WLCA should develop alongside the project.

Who should be involved?

Although the assessment itself is normally undertaken by a sustainability consultant, producing a useful WLCA is a collaborative exercise.

Typically, information comes from:

No single discipline has all the information needed.

The earlier the design team starts sharing information, the more useful the assessment becomes.

Common misconceptions

There are still a few misunderstandings around Whole Life Carbon that regularly come up.

“It’s only needed for large commercial developments.”

Not necessarily. Larger projects are more likely to require a formal assessment, but embodied carbon is becoming relevant across a much wider range of developments as local planning policies evolve.

“The report reduces carbon emissions.”

The report doesn’t reduce carbon by itself.

The assessment provides evidence that helps the design team make informed decisions. The reductions come from changing the design, not from producing another document.

“We’ll do it just before planning.”

Sometimes that’s unavoidable, but leaving a WLCA until the end of the design process usually limits its value.

Before commissioning a Whole Life Carbon Assessment

Every project is different, but it’s useful to have the following information available wherever possible:

Don’t worry if some of this information is still evolving. Early assessments are expected to use assumptions, provided they’re updated as the design progresses.

Looking ahead

It’s unlikely that Whole Life Carbon Assessments will become less important over the next few years.

As operational energy continues to improve through tighter Building Regulations and more efficient building services, embodied carbon will account for a greater proportion of a building’s overall environmental impact. Planning policy is already beginning to reflect that shift.

For architects and planning consultants, the question is gradually changing from “Do we need a Whole Life Carbon Assessment?” to “When should we start thinking about Whole Life Carbon?”

In our experience, projects get the greatest value when carbon is considered early enough to influence design decisions rather than simply documenting those decisions afterwards.

Whether the driver is planning policy, BREEAM or a client’s own sustainability objectives, a Whole Life Carbon Assessment should be viewed as part of the design process—not just another report to submit at the end.

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