Digitising Façade Development

We recently hosted the first session in our Multiplex Technical Talks Programme; ‘Façade Embodied Carbon, using data to target embodied carbon reduction’. Ed Forwood, façade, structure specialist and digital developer, led the evening. With an in-depth explanation of the capabilities of our newly developed automation tool, designed to assess the embodied carbon of façades, Ed explained how it can be used to record all inputs needed for an embodied carbon assessment; to generate a calculation report and record the results.
Neil Dobbs, Head of Façades at Multiplex, led a round table discussion inviting feedback from attending industry experts to conclude the talk. This generated insightful conversation, including how individuals would seek to use the tool, assessing the assumptions behind the calculations it generates and considering the results of the calculation itself.
The evening provided industry experts with a detailed overview of the tool. Ed explained the role we hope it will play in assessing the embodied carbon of all façades procured by Multiplex and others, in due course, across the UK market.
The complexities of the CWCT embodied carbon methodology, increasingly stringent project requirements and the need to work with clients to optimise cost and carbon outcomes makes it imperative that we can provide quick and accurate assessments. This tool makes that possible.
- Neil Dobbs, Head of Façades at Multiplex
Overview
In September 2022, the CWCT issued a new publication; “Embodied Carbon of Façades: A Methodology,” setting out how façade experts should calculate the embodied carbon of façade systems. The methodology sets out how to make appropriate allowances for the many steps or processes followed in the procurement of façades, and is therefore very complex. That’s where our tool comes in – it enables the user to address that complexity by defining and adopting a standardised input data model. By providing a step-by-step view of the calculation process, it allows users to quickly understand what parts of the procurement process are contributing most to the total embodied carbon, and where attention could be best targeted to make reductions.
The tool also proposes a set of functional performance ratings for façade systems, to allow users to review façade embodied carbon outcomes in the context of other façade performance attributes. As our data set expands, this will allow trends and associations to be reviewed and better understood.
Put simply, the tool is intended to minimise the time it takes users to make and partners to review calculations. Intended for iterative use, the tool will reliably inform quality, cost, time and carbon debates. It will allow us to quickly and accurately inform clients how design or procurement choices impact cost and carbon metrics. This will enable clients to optimise their ability to reduce, even through marginal gains, the embodied carbon of the project while respecting budgetary constraint.
Recycled aluminium via Schüco UK used for all the new aluminium curtain wall at 76 Southbank.
Tool Features
The tool structures its input through three main groupings:
2. Glass Schedule
3. Itemised Data Fields
The tool allows the data to be read in from structured json format input files that are expected, in due course, to be auto generated by tools such as Rhino or Revit. The tool also allows input by hand, by the user with various options to make the process faster.
The tool divides the façade assessment between a series of item categories namely:
1. Items other than glass supported by Environmental Product Declarations (EPDs),
2. Glass items,
3. General components,
4. Assembly,
5. construction. The tool structures then set out the embodied carbon accumulation through the various lifecycle modules as defined in BS EN 15643 (A1 to D).
The tool provides several graphical outputs to visualise the distribution of embodied carbon between the façade types and lifecycle modules. It also provides a glass schedule output, tabular ‘carbon distribution’ output summaries, material usage statistics, CWCT template summaries and a comprehensive stand-alone HTML report to allow users to share a read-only view of the assessment made containing all the input data and graphical visualisations.
The tool is browser based, allowing users to record input data and view results as stored on a central server.
Tool Impact
The tool will provide benchmarks and comparative data to help clients understand project specific embodied carbon figures and how their projects and façade systems relate to typical industry practice.


The tool will slash the time it takes to develop embodied
carbon calculations. It will transform their use during the
latter stage of a project from solely a compliance activity to a decision-making activity, thereby allowing marginal gains to be made and different scenarios explored more readily.- Ed Forwood, Façade Consultant
What’s Next?
Our tool is specifically targeted at construction stage embodied carbon calculations allowing our supply chain to quickly and accurately produce calculations compliant with the CWCT methodology whilst also providing quick and easy access to the critical assumptions made in the calculation for reviewers. We are hopeful these are the first steps to an industry accepted standard input data model for embodied carbon calculation.
We hope that uptake of the tool might have other spin-off benefits such as the structured recording of façade items such that it might also enable improvements in ‘urban mine’ stock knowledge.
We would welcome the opportunity to work with specialist contractors to trial our tool and to help us address any issues that might affect uptake.
At Multiplex, we don’t believe in gatekeeping. That’s why we actively share developments like these with our colleagues across the wider industry − we know that real progress is only achieved when we work together.
We know that the benefit of our tool is limited if its use is constrained to Multiplex. As such, we intend to share this more widely, and in so doing make sure that it is suitable for façades on all projects. Our tool represents a new era in embodied carbon calculation for façades. We look forward to further collaborating, hosting more technical talks and striving towards a greener future − as one.