1. We can’t use traditional processes to solve complex, multivariable problems

We need to leverage technology to help simplify them. There are now so many variables to consider that the human brain struggles to respond. Designers need to think about operational and embodied carbon, but also resilience, sea level rise, seismic resistance, safety factors, the potential for incorporating recycled materials or reusing components at end of life. This can result in confusion: where do we start? What does good look like? Getting into a digital environment where everyone is looking at the same thing and understands the parameters can make a massive difference. 
 

2. Reusing existing structures saves 50-75% embodied carbon, and advanced digital modelling will be absolutely critical to understanding the existing asset and working out what can be retained and what can’t

The scope of work is often ambiguous with a retrofit. It’s like peeling an onion – you can’t see what’s there until it’s pulled apart. If there is already a digital model, that’s a much better starting point. You can either strip a building back and then scan the structure, or you can create a digital twin from the original plans, if they’re available. This does take additional time upfront, but it makes the design process a lot faster overall.
 

3. Reaching net-zero through retrofitting existing buildings is achievable, but it will take a fundamental shift in policy and considerable investment

We need to set realistic budgets, based on comprehensive condition assessments and taking into account multiple variables. We also need to reframe our definition of value so that it is broader than just dollars: free-market economics does not drive environmentally sustainable outcomes. Could we get to a dual-currency paradigm for business cases, that measures both cost and carbon, to lead to an optimized solution? A lot of this will come down to the technology that supports designers and decision-makers. With digital modelling that can combine design, cost and carbon data in real time, it becomes possible. 
 

4. Embodied carbon savings are not always justified

Sometimes the lower-carbon option upfront – a less well-insulated thermal envelope or a lower-quality heating system – locks in much higher operational carbon emissions over the life of an asset. This is compounded by the fact that the lifecycle is typically longer than initially intended. Most of the time, the decision-making process isn’t linear, so it becomes a matter of looking at more or less preferred options. Cost is a huge factor. We can add significant value by using software to analyze whole-of-life benchmarking data for different scenarios, to balance capex, opex, operational and embodied carbon in order to reduce the total emissions as far as practically possible.
 

5. We won’t get to net-zero through good design alone

We’ve been using the same set of materials for hundreds of years, and now we need to learn how to use low-carbon alternatives. These will have a huge impact, but they may have different characteristics, so we need to understand the implications for our designs and weigh up the options. Concrete, in particular, is an area where there has been a lot innovation, with the development of new additives and cement replacements, but new products don’t necessarily behave in the same way as the ones we’re used to. We might find that using more of a lower-carbon material results in lower embodied carbon overall, or it might be better to use less of a stronger but more carbon-intensive one. Digital modelling can help us weigh up the options, as well as everything else we have to consider.