Understanding Whole Life Cycle Carbon Assessments in the Planning Context

We have witnessed a significant shift in the construction industry towards more sustainable practices. Among these practices, Whole Lifecycle Carbon Assessments (WLCA) have emerged as a crucial tool in reducing the environmental impact of buildings. These assessments are particularly relevant in the UK, where planning regulations and a growing awareness of climate change are driving the demand for sustainable construction.

What is a Whole Lifecycle Carbon Assessment?

A Whole Lifecycle Carbon Assessment evaluates the total carbon emissions associated with a building over its entire lifecycle. This includes emissions from the production of materials, construction processes, the building’s operational phase, maintenance, and eventual demolition and disposal. By considering all stages, WLCA provides a comprehensive understanding of a building’s carbon footprint.

The Importance of WLCA in the UK

The UK government has committed to achieving net-zero carbon emissions by 2050. The built environment, of which the construction industry is a major component, is responsible for 40% of the country’s carbon emissions, plays a critical role in this ambition. WLCA helps architects, developers, and policymakers identify areas where carbon emissions can be minimised, promoting more sustainable building practices.

Modular structure for WLCA by RICS adapted from British Standards EN 15978, EN 17472 and EN 15643

Key Stages of a Whole Lifecycle Carbon Assessment

  1. Material Production Stages A1-A3: This stage assesses the carbon emissions from extracting raw materials, manufacturing building components, and transporting them to the construction site. Choosing low-carbon materials and local suppliers can significantly reduce emissions at this stage.
  2. Construction Stages A4-A5: Emissions during the construction phase include those from machinery, transportation of materials, and energy consumption on site. Efficient construction practices and renewable energy sources can mitigate these emissions.
  3. Operation B1: The operational phase often accounts for the largest portion of a building’s carbon footprint. This includes energy use for heating, cooling, lighting, and appliances. Designing energy-efficient buildings with advanced insulation, renewable energy systems, and smart technologies is crucial.
  4. Maintenance B2 and Repair B3: Regular maintenance and repairs can contribute to carbon emissions. Using durable materials and designing for easy maintenance can help reduce these emissions over the building’s lifespan.
  5. End of Life C1-C4: This stage evaluates the emissions from demolishing the building and disposing of its materials. Sustainable demolition practices, recycling, and reusing materials can minimize the environmental impact at the end of a building’s life.
    Pie charts illustrating indicative relationships between operational and embodied carbon emissions for three building typologies. RIBA

    Implementing WLCA in Architectural Practice

    Early Design Phase

    Integrating WLCA from the early design phase allows architects to make informed decisions about materials, construction methods, and energy systems. Tools like embodied carbon calculators can aid in simulating and assessing the carbon impacts of different design choices.

    Collaboration and Innovation

    Effective WLCA requires collaboration among architects, engineers, contractors, and sustainability experts. Innovations in materials, such as low-carbon concrete and cross-laminated timber, offer exciting opportunities to reduce emissions. Staying updated with the latest advancements and integrating them into projects is essential.

    Regulatory Compliance

    The London Plan requires major developments to be net-zero carbon and mandates WLCA for major developments. Many London boroughs require Whole Life Cycle Carbon Assessments to be submitted as part of planning applications for new buildings and refurbishments of existing buildings. Westminster council have recently consulted on updating their City Plan with a new policy ‘Retro First’ prioritising retrofitting over demolition extending this requirement for smaller developments. Understanding and adhering to these regulations is vital for architects to ensure their projects meet legal and environmental standards and achieve successful planning outcomes.

    Timber frame construction offers lower embodied carbon compared to steel or concrete

    Challenges and Future Directions

    Despite its benefits, implementing WLCA comes with challenges. Accurate data collection, lack of standardisation, and the complexity of lifecycle analysis can pose difficulties. Where a project is set to replace an existing building, the LPA may request two reviews, to compare emissions associated with refurbishing an existing building with emissions from delivering an entirely new development. However, as the industry progresses, these challenges are being addressed through improved methodologies, databases, and tools.

    Looking ahead, the role of WLCA in the UK’s construction industry will only grow. As we move towards a net-zero future, architects must embrace these assessments to design buildings that are not only functional and aesthetically pleasing but also environmentally responsible.


    Whole Lifecycle Carbon Assessments represent a pivotal step towards sustainable construction in the UK. By comprehensively evaluating a building’s carbon footprint, architects can make informed decisions that significantly reduce environmental impact. As we continue to innovate and refine our practices, WLCA have become an integral part of architectural design, understanding when and how to use them is critical in ensuring successful planning outcomes and helping us build a more sustainable future.



    Westminster City Plan 2019-2040 Regulation 19 Publication Draft March 2024-Policy 43 Retro First

    The London Plan 2021- Chapter 9 Sustainable Infrastructure – Policy SI2 – Minimising Greenhouse Gas Emissions

    London Plan Guidance – Whole Life-Cycle Carbon Assessments – March 2022

    Whole Life Carbon Assessments for the Built Environment – Version 2 2023 – Effective from 1st July 2024

    Embodied and Whole Life Carbon Assessments for Architects – RIBA

    Department of Energy Security & Net Zero – UK Road Map to Net Zero Government Emissions – December 2023