The sustainable life of buildings

Huge amounts of resource are being invested in improving the sustainability of buildings. During 2023, the government announced plans to spend £1.8bn to improve the energy efficiency of housing and the public sector estate, while previous research suggested office landlords could have to allocate as much as £63bn to meet forthcoming energy standards. The journey to net zero undoubtedly requires investment in the built environment, particularly when it comes to reusing existing property. According to the World Green Building Council, property accounts for 39% of energy-related carbon emissions and projections suggest that around 80% of the buildings we have today will still be around in 2050. Counting the cost However, while the perception might be that taking any steps towards net zero can only have a positive effect on a building’s footprint, some changes may come with a significant carbon cost of their own. This is particularly true in “embodied carbon” terms – the energy linked to the extraction and transportation of raw materials – and the manufacturing processes used for building products and technologies. For example, installing solar photovoltaics at an office development can improve its sustainability, certainly on a day-to-day operational basis. But, because of the high embodied carbon cost of the technology, if it is not incorporated in the right way, adding the system could end up prolonging, rather than shortening, the building’s journey to net zero. The system produces around 2,920 tonnes of CO2e (carbon dioxide equivalent) for a monocrystalline PV system that would suit a 10,000 sq m office, equivalent to nearly 50% of the typical footprint associated with such a building. Holistic thinking Net zero, embodied carbon, and a building’s operational footprint can’t be thought about in isolation – introducing green measures might not necessarily cut down a property’s embodied carbon, and vice versa. They need to work together to support the aim of improving the energy efficiency and overall sustainability. There are a number of ways you can reduce the embodied carbon associated with net-zero measures, and sometimes in counter-intuitive ways. For instance, it may be more carbon-friendly in overall terms to keep an existing gas-powered district heating network until it has reached the end of its life, as opposed to installing a completely new system, even if the latter is more environmentally friendly in operational terms. Material choices are another common way of reducing embodied carbon. If you are replacing the façade of a building, while glass imported from abroad is a popular choice, that inevitably incurs additional carbon emissions from transportation compared to alternatives that could be sourced within the country.  Steel is a massive component of many construction projects. It is great to construct with, is robust and durable, and the supply chain is well established. However, every tonne comes with a footprint of nearly twice that figure in carbon. This could be reduced by using recycled steel wherever possible, and sourcing from more sustainable steelworks, which incorporate renewable sources of energy in production processes. That said, at this juncture, this carries a cost with the supply chain yet to be established. Get your priorities right Perhaps most importantly, factor in embodied carbon at the very beginning of a project. Not only will this allow you to make important decisions – such as whether to retain elements of an existing structure or start again from scratch – but upfront calculations will help identify changes where the embodied carbon cost will offset the potential operational gains for quite some time. In some instances, you may find that making fewer changes will help you go further towards net zero. In turn, that could help ensure resources are channelled to the most impactful improvements, while identifying where embodied carbon savings can be made by simply opting to not undertake certain work packages. Reaching net zero is a difficult task in the first place, both action and inaction could have an associated carbon cost, and sometimes the least bad choice may be the only viable decision. But to deliver the most sustainable project possible, consider the full impact that each option may have early on in the process across each measure of potential impact to ensure any additions are not, in fact, counterproductive. Image @ Adobe Stock Grace Mair, Regional director, Thomas & Adamson, part of Egis Group