Marvyn Candler at Lignacite explores why Environmental Product Declarations (EPDs) are now under increasing scrutiny – and how robust, independently verified data supports evidence-based specification and credible carbon reduction in architectural design.
Environmental claims in construction are increasingly questioned by clients, planners and stakeholders. As net zero commitments move from ambition to expectation, architects are under growing pressure to demonstrate that material choices are supported by verifiable evidence. Environmental Product Declarations, commonly referred to as EPDs, provide just that.
For many practices, EPDs are familiar documents. But familiarity does not always translate into understanding. As client, planner and regulator attention increases, it is no longer enough to simply reference an EPD in plans. Architects need confidence in what the data represents, how it has been produced and what that means over the life of a building.
This shift is being reinforced by wider regulatory and cultural change. The Building Safety Act has sharpened the focus on accountability and documentation, while sustainability reporting has moved beyond intent statements towards measurable outcomes. Industry guidance and planning policy increasingly expect whole life carbon assessments to be underpinned by quantified data. In this context, environmental claims and whole life
carbon must be measured from the outset and remain defensible long after a project’s completion.
Understanding EPDs
Before going any further, it’s important to define what an EPD is. An Environmental Product Declaration is a standardised summary of a product’s environmental impact, based on lifecycle assessment methodology. The results are independently verified and presented in a consistent format, providing transparent data on factors such as embodied carbon, resource use and emissions, and allowing meaningful comparison between products.
However, an EPD is not a performance label or a sustainability rating. It does not declare a product to be good or bad. Instead, it provides verified data that enables architects to make informed decisions based on project priorities, context and design intent.
It’s worth mentioning that the source of an EPD matters as much as its content. Not all declarations are produced to the same standard. Independent verification, reputable programme operators and clear system boundaries are essential if data is to be relied upon. Without these, comparisons become unreliable and confidence in specifications is undermined.
In practice, verification involves independent accredited assessors scrutinising the underlying data and assumptions, requesting supporting evidence where needed and challenging any claims that cannot be substantiated.
Lifecycle support
Architects are increasingly expected to justify material choices at early design stages where decisions have a large impact on the total embodied carbon of a project. EPDs support this process by providing comparable data that can be integrated into decision making. Used correctly, they allow teams to identify where material substitutions or specification changes can deliver meaningful reductions.
Lifecycle stages A1 to A4, covering raw material extraction through to transport to site, are particularly significant when assessing embodied carbon. These are the stages most influenced by material choice, yet they often receive less attention than how a building performs once it is in use. Robust EPDs bring this detail into focus, enabling a clearer understanding of the upfront carbon impact.
This is especially relevant when considering materials that are treated as standard or interchangeable, such as concrete blocks. In reality, variations in sourcing, manufacturing processes and transport can result in substantial differences in embodied carbon figures. Evidence based data challenges assumptions and highlights opportunities that might otherwise be missed. Increasingly, there are low-carbon block options available, but it’s important to ensure that claims are supported by verified data.
Accreditation agenda
EPDs also play an important role in supporting whole-life carbon assessments and environmental assessment frameworks, such as BREEAM – the Building Research Establishment Environmental Assessment Method – which is widely used to benchmark the environmental performance of buildings. These increasingly rely on verified data, reinforcing the importance of robust information at the specification stage. While an EPD alone does not secure credits, it provides the verified information required to support compliance and demonstrate intent. More importantly, it strengthens the credibility of sustainability narratives presented to clients and stakeholders.
As expectations rise, architects are being asked not only to reduce carbon but to prove how those reductions are achieved. Specifications supported by third-party verified data reduce the risk of later challenge and provide clarity when decisions are revisited during procurement, construction or post-completion review.
EPDs do not sit in isolation, either. They fit alongside accreditations for responsible sourcing standards, such as BES 6001, quality management systems and transparent supply chains. Together, these elements support a rigorous approach to specification that aligns environmental ambition with practical delivery. Products supported by independently verified EPDs and BES 6001 certifications with strong scores (i.e. Very Good or Excellent) can help projects achieve higher BREEAM ratings.
This joined up evidence base is becoming more important as sustainability considerations are assessed not just at the planning stage, but throughout procurement, construction and post-completion review. In this context, the ability to demonstrate how and why materials were specified carries growing weight, particularly on complex projects.
The conversation around environmental claims isn’t going away. If anything, it’s intensifying. As reporting requirements tighten and industry understanding matures the architects who can confidently read, question and compare EPDs will find themselves better equipped to defend decisions, secure client confidence and deliver projects that withstand scrutiny long after completion.
This isn’t about adding administrative tasks. EPDs offer architects greater control over carbon outcomes and stronger evidence to support design intent. In an environment where sustainability claims are being questioned more rigorously, verified data becomes a strategic advantage. The practices that embrace this now will be specifying with clarity and credibility while others are still catching up.
Marvyn Candler is SHEQ manager at Lignacite